This is a replacement Blade Main Blade Shim Set, and is intended for use with the Blade 450 and 450 X helicopters.
Wednesday, Sep 11 2019 (about a year ago)
Blade Main Blade Shim Set (4)
These serve the purpose. Make of hard plastic. For blade grips using M3 bolts. Thickness is ~0.80mm. OD is 13mm.