This sale is for one very rare near mint condition Mamiya RZ67 / RB67 105mm front lens cap, suitable for use with the RB67 and RZ67 75mm Shift and 500mm f6 Apo lenses.
This Mamiya cap has minimal signs of use. It is about 107mm internally, and is a push fit for the 75mm Shift and 500mm f6 Apo lenses (105mm filter size). If you want a few caps (or other sizes), just ask.