It's very comfortable to press on the button. The button surface and edge are very smooth. | [ADVANTAGE] We are equipped with one black plastic o-rings,so that the button is tightly integrated with the camera.(To prevent falling off ). | [Material] Made of High quality Brass and Stone-Handmade.1x Convex Copper inlaid stone Release Buttons,1X Black O-ring. | Diameter: 11mm | [Compatibility]: Fujifilm X-PRO2, XPRO-1,X100F, X100T, X100, X100S, X10, X20, X30, X-E1, X-E2,X-E2S, STX-2, X-T10/ Leica M1, M2, M3, M6, M7, M8, M9, M-E, M-P, M9-P, M-A, M-Monochrom M Type 240/ Can on F-1, New F-1, AE-1 (FD mount)/ Nikon Df, M2, F3/ Sony RX1R II, RX10 II/ Other Brands Minolta XD7, Minolta SR-7, Rolleiflex (LM mount), Olympus OM-1,PEN-F.(Note:Fits any shutter button with a threaded hole)