Bathtub faucet handle plastic piece broke not sure where to find

[Pamelardanie]

Hi there,
I have a jet tub and the hot water handle quit working due to broken piece inside that allows it to grip when turned. I need help identifying the piece and where to find replacement. Please help. I attached photo.

 

[Mr_David]

Kohler GP77005-rp hot

 

[LockePlumbing]

It's American Standard

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