Fittest FC-501 Quick Release Assembly Clamp Adapter 1. Brand new and high quality. 2. This high-quality quick release plate can be used as a replacement for Manfrotto 577, compatible for Manfrotto tripod. 3. Comes with one 1/4 inch and one 3/8 inch screw for your camera or camcorder mounting. 4. With two 1/4 inch and one 3/8 inch screw holes at bottom for ball head, tripod or camera dolly mounting. 5. The base features horizontal & vertical three shooting gradienters for better calibration. 6. The quick release sliding plate is compatible with for Manfrotto 501PL and 501PL (long). 7. Features solid locking screw, safety pin & anti-skid pads on the plate, providing you quite reliable mounting of your camera. 8. Made of aluminium alloy, very durable.