Special Note: Mount M42/M48/M54 Rings Only must be used with our red selector ring and cannot be used alone Product features: 1. Adopt modular combination structure, M42/M48/M54 three screw structures can be used interchangeably. 2. The swing screw of the handle is made of stainless steel, the screw is thicker, the strength is higher, and the appearance is beautiful. 3. Silicone damping ring is used for the damping of the rotating structure to reduce the pollution caused by the leakage of damping oil. Appearance 1. The combination of red and black is more beautiful and atmospheric. 2. The shape structure is designed with anti-slip teeth. The assembly structure and the screw ring are connected with 5 stainless steel screws, and a wrench is provided. M42 CAA 360 Rotary Composition Adjuster Thickness extension: 12.5MM M42*0.75 external thread: 3MM M42*0.75 internal thread: 5MM ======================================== M48 CAA 360 Rotary Composition Adjuster Thickness extension: 12.5MM M48 external thread: 3MM M48 internal thread: 5MM ================================================ M54 CAA 360 Rotary Composition Adjuster Thickness extension: 12.5MM M54*0.75 external thread: 3MM M54*0.75 internal thread: 5MM