The used Kaiser 100mm Push-On Lens Cap is designed to fit any camera, enlarger lens, binocular, tele-, micro-, or spotting scope lens.
The actual size needed depends on the lens in question. The cap should fit snuggly but not so tight that it is hard to remove.
Covers
Kaiser
Accessory
ATS Rentals has recently been acquired by Lensrentals and has ceased accepting new orders.