M42-EOS/EF Electric Adapter Ring for M42 Lens for Canon EOS/EF Mount Camera Features: A great solution to unify your camera parts. Made of durable aluminum alloy material and built.  M42 mount lenses (for Zeiss, Pentax, Praktica, Mamiya, Zenit) can be used for Canon EOS cameras such as 5D, 5D2, 5D3, 7D, 60D, 450D, 550D, 600D, 750D, 760D and so on.  There is no rome connection on the ring so diaphragm control of the lens is set manually.  It is possible to have macro rings and other accessories.  Support focus on infinity.  Specification: Color: black Material: Metal Compatible Lens: for M42 Lens  Compatible Camera: For Canon EOS 5D, 5D2, 5D3, 7D, 60D, 450D, 550D, 600D, 750D, 760D and so on Dimensions: Approx. 6.3*6.3*1cm/2.5*2.5*0.4in Weight: Approx. 28g Package List:  1 x M42-EOS/EF Adapter ring