I have a Mamiya Sekor 135mm F4.5 lens unit for Mamiya C TLR's listed right now. It's in fair condition, with cleaning marks on the front and back elements of the taking lens and a small decoated area on the front of the viewing lens. The shutter fires at all speeds but sometimes sticks before firing and needs to be "nudged." 1/2s and 1s are noticeably slow. All in all it just needs a CLA. The aperture looks good and has no oil or residue on it.