The JJC soft release buttons kit includes 2 pcs in the packaging, One is convex surface with a diameter of 10mm, the other one is concave surface with a diameter of 11mm. Both the 2 soft release buttons are made of brass and ensure a comfortable finger touch at the top of your camera. Just screw the soft release button into shutter release button's thread on your camera and you will enjoy the soft and steady shutter release operation. In addition, it decorates your camera, which will make your camera look more stylish and elegant. After it is mounted on your camera, each time you capture a photo, you can feel its smooth soft surface. Additionally, two rubber rings are included in the package, which are mainly used for Fujifilm X series cameras to ensure a tight attachment, while they are not used for Sony RX1 & RX10 series cameras. Below are a list of some of the compatible cameras: Fujifilm: X-T4 / X-T3 / X-T2 / X-T30 / X-T20 / X-T10 / X-PRO3 / X-PRO2 / X-PRO1 / X100V / X100F / X100T / X100S / X100 / X30 / X20 / X10 / X-E3 / X-E2S / X-E2 / X-E1 / STX-2 Leica: M9 / M8 / M7 / M6 / M3 / M2 / M1 / M-E / M-P / M9-P / M-A / M-Monochrom / M Type 240 Canon: New F-1 / F-1 / AE-1 (FD mount) Nikon: Df / M2 / F3 Sony: DSC-RX1R II / DSC-RX10 IV / DSC-RX10 III / DSC-RX10 II / DSC-RX10 Other Brands: Minolta XD7 / Minolta SR-7 / Rollei (LM mount) / Olympus OM-1 / Hassellad 503CW Note: It also fits other cameras with a standard threaded shutter release socket which is designed by the camera manufacturers to accept a mechanical shutter release cable.