Mamiya Sekor 65mm 4.5, that is on my Mamiya RB67 Pro. S. It has both front and rear caps. I do believe it fits most systems in the RB RZ format, however, please research this! I am selling to ay off some bills, sadly, and therefore it needs to sell ASAP! I am in California, for shipping purposes, I may ship worldwide, you pay actual ship fee's via USPS Priority international. I am asking $200 with USA only USPS Priority Ship. Lens barrel shows some normal wear but is mechanically sound. Aperture blades move smoothly. Shutter fires at all speeds. Lens optics are clear of fungus and scratches. Please ask queastions anytime, and I'll respond ASAP!