A lens cap for Fujica X Mount that was used on Fujica AX, STX and Porst CR and some other cameras (late 1970-1985).
Modelled after what seems to be an original plastic lens cap for Fujica X Mount.
source:
https://cad.onshape.com/documents/b8044b5d1302cb493d9cff62/w/57e18ffc7e6ff87d19359325/e/054b190f562fb548d6da5b7f?renderMode=0&uiState=6686d64bc1e25064f65be5a7
The author marked this model as their own original creation.