Description This adapter allows C Mount Lens to be used on M42 screw mount body. Or for modify lens purpose. Features C mount lens to M42 screw thread adapter The AF doesn't function and not allows to keep the infinity focus Made of anodized aluminum camera body mount, smooth surface Finishing Install, remove and operate lens smoothly Female mount (inner) : C Mount (diameter 25.4mm) Male mount (outer) : 42mm(diameter) x 1mm Material: aluminium Note Although the lens will fit physically,automatic diaphragm,auto-focusing,or any other function will not operate correctly while using this adapter. In this case "Stop-down mode"will need to be used when metering since the lens doesn't have the ability to have its apeture controlled by camera body.You can shoot with manual mode or apeture priority mode. Campatible With Lens: C mount Lens. Package Included 1 x C Mout Lens to M42 Adapter