diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index eced260..899fd5e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -13,7 +13,6 @@ jobs:
       fail-fast: true
       matrix:
         version:
-          - '1.3'
           - '1.5'
           - 'nightly'
         os:
diff --git a/InteractModels/Project.toml b/InteractModels/Project.toml
index 9ef3b36..0397583 100644
--- a/InteractModels/Project.toml
+++ b/InteractModels/Project.toml
@@ -12,7 +12,7 @@ Reexport = "189a3867-3050-52da-a836-e630ba90ab69"
 Interact = "0.10"
 ModelParameters = "0.3"
 Reexport = "0.2, 1"
-julia = "1"
+julia = "1.5"
 
 [extras]
 DataFrames = "a93c6f00-e57d-5684-b7b6-d8193f3e46c0"
diff --git a/Project.toml b/Project.toml
index c64ea43..5e5f533 100644
--- a/Project.toml
+++ b/Project.toml
@@ -20,7 +20,7 @@ Flatten = "0.4"
 PrettyTables = "0.8, 0.9, 0.10, 0.11, 0.12, 1"
 Setfield = "0.6, 0.7, 0.8"
 Tables = "1"
-julia = "1"
+julia = "1.5"
 
 [extras]
 Aqua = "4c88cf16-eb10-579e-8560-4a9242c79595"
diff --git a/src/ModelParameters.jl b/src/ModelParameters.jl
index 7b9cc29..c40a658 100644
--- a/src/ModelParameters.jl
+++ b/src/ModelParameters.jl
@@ -14,6 +14,8 @@ import AbstractNumbers,
        Tables 
 
 using Setfield
+
+using Base: tail
       
 export AbstractModel, Model, StaticModel
 
diff --git a/src/model.jl b/src/model.jl
index c8da2e2..235a844 100644
--- a/src/model.jl
+++ b/src/model.jl
@@ -83,8 +83,10 @@ abstract type AbstractModel end
 Base.parent(m::AbstractModel) = getfield(m, :parent)
 setparent(m::AbstractModel, newparent) = @set m.parent = newparent
 
-params(m::AbstractModel) = params(parent(m))
-stripparams(m::AbstractModel) = stripparams(parent(m))
+params(m::AbstractModel; kw...) = params(parent(m); kw...)
+stripparams(m::AbstractModel; kw...) = stripparams(parent(m); kw...)
+paramfieldnames(m::AbstractModel; kw...) = paramfieldnames(parent(m); kw...)
+paramparenttypes(m::AbstractModel; kw...) = paramparenttypes(parent(m); kw...)
 function update(x::T, values) where {T<:AbstractModel} 
     hasfield(T, :parent) || _updatenotdefined(T)
     setparent(x, update(parent(x), values))
@@ -92,8 +94,6 @@ end
 
 @noinline _update_methoderror(T) = error("Interface method `update` is not defined for $T")
 
-paramfieldnames(m) = Flatten.fieldnameflatten(parent(m), SELECT, IGNORE)
-paramparenttypes(m) = Flatten.metaflatten(parent(m), _fieldparentbasetype, SELECT, IGNORE)
 
 _fieldparentbasetype(T, ::Type{Val{N}}) where N = T.name.wrapper
 
@@ -102,64 +102,64 @@ _fieldparentbasetype(T, ::Type{Val{N}}) where N = T.name.wrapper
 
 # It may seem expensive always calling `param`, but flattening the
 # object occurs once at compile-time, and should have very little cost here.
-Base.length(m::AbstractModel) = length(params(m))
-Base.size(m::AbstractModel) = (length(params(m)),)
-Base.first(m::AbstractModel) = first(params(m))
-Base.last(m::AbstractModel) = last(params(m))
+Base.length(m::AbstractModel; kw...) = length(params(m; kw...))
+Base.size(m::AbstractModel; kw...) = (length(params(m; kw...)),)
+Base.first(m::AbstractModel; kw...) = first(params(m; kw...))
+Base.last(m::AbstractModel; kw...) = last(params(m; kw...))
 Base.firstindex(m::AbstractModel) = 1
-Base.lastindex(m::AbstractModel) = length(params(m))
+Base.lastindex(m::AbstractModel; kw...) = length(params(m; kw...))
 Base.getindex(m::AbstractModel, i) = getindex(params(m), i)
 Base.iterate(m::AbstractModel) = (first(params(m)), 1)
 Base.iterate(m::AbstractModel, s) = s > length(m) ? nothing : (params(m)[s], s + 1)
 
 # Vector methods
-Base.collect(m::AbstractModel) = collect(m.val)
-Base.vec(m::AbstractModel) = collect(m)
-Base.Array(m::AbstractModel) = vec(m)
+Base.collect(m::AbstractModel; kw...) = collect(m[:val; kw...])
+Base.vec(m::AbstractModel; kw...) = collect(m; kw...)
+Base.Array(m::AbstractModel; kw...) = vec(m; kw...)
 
 # Dict methods - data as columns
 Base.haskey(m::AbstractModel, key::Symbol) = key in keys(m)
 Base.keys(m::AbstractModel) = _keys(params(m), m)
 
-@inline function Base.setindex!(m::AbstractModel, x, nm::Symbol)
+@inline function Base.setindex!(m::AbstractModel, x, nm::Symbol; kw...)
     if nm == :component
         erorr("cannot set :component index")
     elseif nm == :fieldname
         erorr("cannot set :fieldname index")
     else
         newparent = if nm in keys(m)
-            _setindex(parent(m), Tuple(x), nm)
+            _setindex(parent(m), Tuple(x), nm; kw...)
         else                                 
-            _addindex(parent(m), Tuple(x), nm)
+            _addindex(parent(m), Tuple(x), nm; kw...)
         end
         setparent!(m, newparent)
     end
 end
 # TODO do this with lenses
-@inline function _setindex(obj, xs::Tuple, nm::Symbol)
+@inline function _setindex(obj, xs::Tuple, nm::Symbol; select=SELECT, ignore=IGNORE)
     lens = Setfield.PropertyLens{nm}()
-    newparams = map(params(obj), xs) do par, x
-        Param(Setfield.set(parent(par), lens, x))
+    newparams = map(params(obj; select, ignore), xs) do p, x
+        setparent(p, Setfield.set(parent(p), lens, x))
     end
-    Flatten.reconstruct(obj, newparams, SELECT, IGNORE)
+    Flatten.reconstruct(obj, newparams, select, ignore)
 end
-@inline function _addindex(obj, xs::Tuple, nm::Symbol)
-    newparams = map(params(obj), xs) do par, x
-        Param((; parent(par)..., (nm => x,)...))
+@inline function _addindex(obj, xs::Tuple, nm::Symbol; select=SELECT, ignore=IGNORE)
+    newparams = map(params(obj), xs) do p, x
+        setparent(p, (; parent(p)..., (nm => x,)...))
     end
-    Flatten.reconstruct(obj, newparams, SELECT, IGNORE)
+    Flatten.reconstruct(obj, newparams, select, ignore)
 end
 
 _keys(params::Tuple, m::AbstractModel) = (:component, :fieldname, keys(first(params))...)
 _keys(params::Tuple{}, m::AbstractModel) = ()
 
-@inline function Base.getindex(m::AbstractModel, nm::Symbol)
+@inline function Base.getindex(m::AbstractModel, nm::Symbol; kw...)
     if nm == :component
-        paramparenttypes(m)
+        paramparenttypes(m; kw...)
     elseif nm == :fieldname
-        paramfieldnames(m)
+        paramfieldnames(m; kw...)
     else
-        map(p -> getindex(p, nm), params(m))
+        map(p -> getindex(p, nm), params(m; kw...))
     end
 end
 
@@ -181,16 +181,15 @@ end
 
 setparent!(m::AbstractModel, newparent) = setfield!(m, :parent, newparent)
 
-update!(m::AbstractModel, vals::AbstractVector{<:AbstractParam}) = update!(m, Tuple(vals))
-function update!(params::Tuple{<:AbstractParam,Vararg{<:AbstractParam}})
-    setparent!(m, Flatten.reconstruct(parent(m), params, SELECT, IGNORE))
+function update!(m::AbstractModel, vals::AbstractVector{<:AbstractParam}; kw...)
+    update!(m, Tuple(vals); kw...)
 end
-function update!(m::AbstractModel, table)
+function update!(m::AbstractModel, table; kw...)
     cols = (c for c in Tables.columnnames(table) if !(c in (:component, :fieldname)))
     for col in cols
-        setindex!(m, Tables.getcolumn(table, col), col)
+        setindex!(m, Tables.getcolumn(table, col), col; kw...)
     end
-    m
+    return m
 end
 
 """
@@ -220,30 +219,34 @@ mutable struct Model <: AbstractModel
 end
 Model(m::AbstractModel) = Model(parent(m))
 
-@inline @generated function _update_params(ps::P, values::Union{<:AbstractVector,<:Tuple}) where {N,P<:NTuple{N,Param}}
+const ParamTuple = Tuple{Vararg{<:AbstractParam}}
+
+@inline @generated function _update_params(ps::P, values::Union{<:AbstractVector,<:Tuple}) where {P<:ParamTuple}
     expr = Expr(:tuple)
-    for i in 1:N
-        expr_i = :(Param(NamedTuple{keys(ps[$i])}((values[$i], Base.tail(parent(ps[$i]))...))))
+    for i in 1:length(ps.parameters)
+        expr_i = :(setparent(ps[$i], NamedTuple{keys(ps[$i])}((values[$i], tail(parent(ps[$i]))...))))
         push!(expr.args, expr_i)
     end
     return expr
 end
 
-update(x, values) = _update(ModelParameters.params(x), x, values)
-@inline function _update(p::P, x, values::Union{<:AbstractVector,<:Tuple}) where {N,P<:NTuple{N,Param}}
-    @assert length(values) == N "values length must match the number of parameters"
-    newparams = _update_params(p, values)
-    Flatten.reconstruct(x, newparams, SELECT, IGNORE)
+update(x, values; kw...) = _update(ModelParameters.params(x), x, values; kw...)
+@inline function _update(ps::P, x, values::Union{<:AbstractVector,<:Tuple};
+    select=SELECT, ignore=IGNORE
+) where {P<:ParamTuple}
+    @assert length(values) == length(ps) "values length must match the number of parameters"
+    newparams = _update_params(ps, values)
+    return Flatten.reconstruct(x, newparams, select, ignore)
 end
-@inline function _update(p::P, x, table) where {N,P<:NTuple{N,Param}}
-    @assert size(table, 1) == N "number of rows must match the number of parameters"
+@inline function _update(ps::P, x, table; select=SELECT, ignore=IGNORE) where {P<:ParamTuple}
+    @assert size(table, 1) == length(ps) "number of rows must match the number of parameters"
     colnames = (c for c in Tables.columnnames(table) if !(c in (:component, :fieldname)))
-    newparams = map(p, tuple(1:N...)) do param, i
-        let names = keys(param);
-            Param(NamedTuple{names}(map(name -> Tables.getcolumn(table, name)[i], names)))
+    newparams = map(ps, tuple(1:length(ps)...)) do p, i
+        let names = keys(p);
+            setparent(p, NamedTuple{names}(map(name -> Tables.getcolumn(table, name)[i], names)))
         end
     end
-    Flatten.reconstruct(x, newparams, SELECT, IGNORE)
+    return Flatten.reconstruct(x, newparams, select, ignore)
 end
 
 """
@@ -270,17 +273,17 @@ StaticModel(m::AbstractModel) = StaticModel(parent(m))
 
 # Model Utils
 
-_expandpars(x) = Flatten.reconstruct(parent, _expandkeys(parent), SELECT, IGNORE)
+_expandpars(x) = Flatten.reconstruct(parent, _expandkeys(parent), select, ignore)
 # Expand all Params to have the same keys, filling with `nothing`
 # This probably will allocate due to `union` returning `Vector`
 function _expandkeys(x)
     pars = params(x)
     allkeys = Tuple(union(map(keys, pars)...))
-    return map(pars) do par
+    return map(pars) do p
         vals = map(allkeys) do key
-            get(par, key, nothing)
+            get(p, key, nothing)
         end
-        Param(NamedTuple{allkeys}(vals))
+        setparent(p, NamedTuple{allkeys}(vals))
     end
 end
 
diff --git a/src/param.jl b/src/param.jl
index 098921e..1607a58 100644
--- a/src/param.jl
+++ b/src/param.jl
@@ -15,16 +15,18 @@ function ConstructionBase.setproperties(p::P, patch::NamedTuple) where P <: Abst
     P.name.wrapper(fields)
 end
 
-@inline withunits(m, args...) = map(p -> withunits(p, args...), params(m))
+@inline withunits(x, args...; kw...) = map(p -> withunits(p, args...), params(x; kw...))
 @inline function withunits(p::AbstractParam, fn::Symbol=:val)
     _applyunits(*, getproperty(p, fn), get(p, :units, nothing))
 end
 
-@inline stripunits(m, xs) = map(stripunits, params(m), xs)
+@inline stripunits(x, xs; kw...) = map(stripunits, params(x; kw...), xs)
 @inline function stripunits(p::AbstractParam, x)
     _applyunits(/, x, get(p, :units, nothing))
 end
 
+setparent(m::P, newparent) where P<:AbstractParam = P.name.wrapper(newparent)
+
 # Param might have `nothing` for units
 @inline _applyunits(f, x, units) = f(x, units)
 @inline _applyunits(f, x, ::Nothing) = x
@@ -42,9 +44,11 @@ Base.values(p::AbstractParam) = values(parent(p))
 @inline Base.getproperty(p::AbstractParam, x::Symbol) = getproperty(parent(p), x)
 @inline Base.get(p::AbstractParam, key::Symbol, default) = get(parent(p), key, default)
 @inline Base.getindex(p::AbstractParam, i) = getindex(parent(p), i)
+Base.parent(p::AbstractParam) = getfield(p, :parent)
 
 
 # AbstractNumber interface
+
 Base.convert(::Type{Number}, x::AbstractParam) = AbstractNumbers.number(x)
 Base.convert(::Type{P}, x::P) where {P<:AbstractParam} = x
 AbstractNumbers.number(p::AbstractParam) = withunits(p)
@@ -79,15 +83,20 @@ end
 Param(val; kwargs...) = Param((; val=val, kwargs...))
 Param(; kwargs...) = Param((; kwargs...))
 
-Base.parent(p::Param) = getfield(p, :parent)
-
-# Methods for objects that hold params
-params(x) = Flatten.flatten(x, SELECT, IGNORE)
-stripparams(x) = hasparam(x) ? Flatten.reconstruct(x, withunits(x), SELECT, IGNORE) : x
+params(x; select=SELECT, ignore=IGNORE) = Flatten.flatten(x, select, ignore)
+function stripparams(x; select=SELECT, ignore=IGNORE)
+    hasparam(x) ? Flatten.reconstruct(x, withunits(x), select, ignore) : x
+end
+function paramfieldnames(x; select=SELECT, ignore=IGNORE)
+    Flatten.fieldnameflatten(x, select, ignore)
+end
+function paramparenttypes(x; select=SELECT, ignore=IGNORE)
+    Flatten.metaflatten(x, _fieldparentbasetype, select, ignore)
+end
 
 
 # Utils
-hasparam(obj) = length(params(obj)) > 0
+hasparam(obj; kw...)  = length(params(obj; kw...)) > 0
 
 _checkhasval(nt::NamedTuple{Keys}) where {Keys} = first(Keys) == :val || _novalerror(nt)
 # @noinline avoids allocations unless there is actually an error
diff --git a/src/tables.jl b/src/tables.jl
index 94db809..953fc37 100644
--- a/src/tables.jl
+++ b/src/tables.jl
@@ -10,7 +10,7 @@ _columntypes(m) = map(k -> Union{map(typeof, getindex(m, k))...}, keys(m))
 # As Columns
 Tables.columnaccess(::Type{<:AbstractModel}) = true
 Tables.columns(m::AbstractModel) = m
-Tables.getcolumn(m::AbstractModel, nm::Symbol) = collect(getindex(m, nm))
-Tables.getcolumn(m::AbstractModel, i::Int) = collect(getindex(m, i))
-Tables.getcolumn(m::AbstractModel, ::Type{T}, col::Int, nm::Symbol) where T = 
-    collect(getindex(m, nm))
+Tables.getcolumn(m::AbstractModel, nm::Symbol; kw...) = collect(getindex(m, nm; kw...))
+Tables.getcolumn(m::AbstractModel, i::Int; kw...) = collect(getindex(m, i; kw...))
+Tables.getcolumn(m::AbstractModel, ::Type{T}, col::Int, nm::Symbol; kw...) where T = 
+    collect(getindex(m, nm; kw...))
diff --git a/test/runtests.jl b/test/runtests.jl
index bc9e2cc..0c84283 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -246,3 +246,28 @@ end
     @test isa(tuplegroups.A.i, Tuple)
     @test isa(tuplegroups.B.j, Tuple)
 end
+
+struct FreeParam{T,P<:NamedTuple} <: AbstractParam{T}
+    parent::P
+end
+FreeParam(nt::NT) where {NT<:NamedTuple} = begin
+    ModelParameters._checkhasval(nt)
+    FreeParam{typeof(nt.val),NT}(nt)
+end
+FreeParam(val; kwargs...) = FreeParam((; val=val, kwargs...))
+FreeParam(; kwargs...) = FreeParam((; kwargs...))
+
+@testset "spefify param type" begin
+    sf = S2(
+        FreeParam(99),
+        FreeParam(7),
+        Param(100.0; bounds=(50.0, 150.0))
+    )
+    @test params(sf; select=FreeParam) == (FreeParam(99), FreeParam(7))
+    m = Model(sf)
+    @test m[:val, select=Param] == (100.0,)
+    @test getindex(m, :val; select=FreeParam) == (99, 7)
+    m[:bounds, select=FreeParam] = ((1, 100), (1, 10)) 
+    @test m[:bounds] == ((1, 100), (1, 10), (50.0, 150.0))
+end
+