You are looking at a Paper Shim Kit for any Fender-Rhodes Piano with Wood Keys.
These high quality paper shims were cut from hydraulic card and therefore are humidity proof as well as much stronger than regular paper shims.
The kit comes with 3 types of shims:
a) 0.75mm width
b) 0.35 width
c) 0.15 width
These 3 types of shims will allow you to allign your keyboard to the finest detail.
Highly recommended if you are overhauling the piano's action or if you are just alligning the keyboard.