This is a listing for a Leica Leitz logo M-mount lens rear cap, which is in fairly good condition with some signs of age. This cap is useful for the following reasons: This rear cap has three claws on the back that securely engage with the notches of a cut-out type LM ring, allowing for smooth removal. This cap is essential for those who use LM rings. I've collected many of these lens caps, but you need to be careful when buying this lens rear cap. I've found many that don't lock properly even when attached to a lens, even if they look clean. Loose caps are useless. This one fits securely on my lenses. I've thought about it, and I think the reason so many are loose is probably because users overtighten them. The mount claws are made of resin, not metal, so I think they can wear out or the grooves can be crushed. If you stop turning once it's reasonably tight, it will last longer. The exterior shows some age, but it still has a shine and you can continue to use it comfortably. It's an essential accessory for protecting your valuable lenses. If you're looking for one, please consider it. Not only for Leica fans, but also for Nikon and Hasselblad fans.