The LEICAVIT M fast winder is mounted in place of the base cover, and allows experienced photographers to shoot up to two frames per second without taking the camera from their eye - independent of batteries. Just unfold the lever, pull it back to its limit to wind the film, and take the picture. The lever returns under spring pressure so you can repeat the sequence as quickly as possible. The Leicavit-M fits the LEICA MP, M7, M6TTL, M6, M4-P and M4-2.