Allow M39 mount lenses used on Fujifilm X series camera body. Compatible with Fujifilm camera includes: Fuji X-A1, X-A2, X-A3, X-E1, X-E2, X-E3, X-M1, X-Pro1, X-Pro2, X-S1, X-T1, X-T10, X-T20, X-T2, X10, X20, X30, XF1, XQ1, XQ2 etc. Made of brass and aluminum. Stable,precise and durable construction.Manually operated.Infinity focus allowed. For heavy medium format lenses, we suggest to use with a telephoto bracket and a tripod to balance its weight when shoot.