This is a handgrip for all Leica M film cameras, except the M5. It mounts over the bottom plate, with the help of a coin, attaches to the tripod mount, but the advantage is that it gives you a tripod mount at the center of the handgrip, which corrects the mount of M film cameras which inconveniently is located on the side. They did a great job. The fun fact is that it also has a storage for 5 x batteries inside the handgrip. Genius. You can use it on M6, M7, and MP, as I've used it on all. I'm not sure about older Ms. it's a silver version, which worked perfectly with my M7 silver shown in the picture. It's the best handgrip I had and worked perfectly when I used it. It can permanently be attached to the bottom plate, so you'll never have to remove it from the bottom plate. Because you have access to the latch that opens up the bottom of the camera for film retrieval. Any other questions please ask.
