1. Slide-stopping rubber mats to prevent the camera/lens from moving while changing the position of the head. 2. Patented SIRUI safety lock design, that prevents your camera from accidentally sliding off of the head when you slightly loosen the Quick Release Clamp (to make adjustments to the positioning of your equipment). 3. Arca-compatible 4. Has a special slot for use with today's popular camera straps - no need to remove the strap to attach the QR plate onto the head. 5. Comes with 2 screws - one with a pop-up handle for the center position - one basic screw for the side positions. 6. Sirui ?K-40X replacement