Type 1 M42 Screw Mount to EOS Camera Lens Adapter

This is an unused Type 1 M42 screw mount to EOS camera mount. It was made in China.

Type 2 adapters have a shelf or lip in the adapter to depress the aperture pin in the base of the lens. Type 1 M42 digital camera adapters do not have this shelf and are used when the lens has no aperture pin, or where the aperture pin does not depress fully into the base (e.g., Yashinon lenses made for the Yashica Penta J camera series). Most of these adapted lenses are functional manual lenses so you do not need to depress the pin when adapting the lens to a digital camera. The M42 screw mount is also referred to as the Universal screw mount or Pentax thread mount.