Freezywater,
So many 'helpers" , you are lucky.
The part you need, is it the inner sole which goes into the boot liner?
Or
Is it the heel wedge which goes on the boot sole plate?
Or is it the plastic plate which goes UNDER the ski boot lin er?
They are all very different.
The heel wedge you can get at any ski shop. They cost $2-4.
The plastic sole UNDER the ski boot liner you can also get at any shop however as ise noted you must check how it is "interfaced" with boot shell. Some have screws some have plugs!
As far as liner soles, you can also get them at any ski shop . If not I have about 50 units which I can send you!
Hope this helps you!
