KMZ 50mm f3.5 Industar-50-2 for M42
The KMZ Industar-50-2 is a Soviet-made lens for M42 with a slightly misleading name (it’s a 50mm f3.5), but in its defense, it’s tiny: not just short (about 2cm long from the mount) but also just under 5cm across at the mount. It looks like a rangefinder lens, but it’ll mount to any M42 SLR. This Industar is in very good cosmetic condition, with minor paint wear. Optics have been cleaned, and retain a tiny bit of fungus etching in the coating at the edge of the front element (don’t worry, the actual fungus is long gone).