Rear lens cap depth is about 30mm for rangefinder prewar 35mm f/2.8 Biogon. Zeiss Contax rangefinder camera lenses  prewar Biogon 35mm f/2.8, Russia Kiev camera wide angle lens Jupiter 35mm f/2.8. See the picture. Also fits Nikon rangefinder wide lens. 

Good luck and thank you for bidding.