Feature 1 It allows you to use for Praktica PB mount lens on for Canon EOS EF mount SLR/DSLR camera. 2 With focus cue tone for its electric contact, more convenient than the normal adapter rings. 3 Saving you the expense of a costly and irreversible conversion. 4 Made of quality alloy material in silver color. 5 It is possible to supports AV mode. Features: It allows you to use for Praktica PB mount lens on for Canon EOS EF mount SLR/DSLR camera. With focus cue tone for its electric contact, more convenient than the normal adapter rings. Saving you the expense of a costly and irreversible conversion. Made of quality alloy material in silver color. It is possible to supports AV mode. Only manual focusing available Able to focus infinity. Specification: Color: Silver Material: Alloy Compatible Lens: for Praktica PB mount lens Compatible Camera: for Canon EOS EF mount camera (for Canon 5D Mark IV, 6D Mark II, there is No focus cue tone.) Diameter: Approx. 6.5cm / 2.6in Weight: Approx. 32g Package List: 1 * Lens Adapter Ring