M42 lens mount
SCREW THREAD MOUNTING STANDARD FOR ATTACHING LENSES TO 35 MM CAMERAS
Pentax Universal Screw Mount; Pentax screw; Praktica thread mount; Praktica screw mount; Praktica mount; M42 screw mount; M42 mount; M42-mount; M42 screw lens mount
The M42 lens mount is a screw thread mounting standard for attaching lenses to 35 mm cameras, primarily single-lens reflex models. It is more accurately known as the M42 × 1 mm standard, which means that it is a metric screw thread of 42 mm diameter and 1 mm thread pitch.