From Manufacturer
The Magnus VT-QRP600 Sliding Balance Plate for VT-5000/6000 Tripods is a sliding balance plate for your VT-5000 and VT-6000 tripod. It is an exact replacement for the plate that came with your tripod. It comes with 1/4"-20 and 3/8"-16 camera mounting screws and features a spring-loaded locating pin for camcorders. At 4.7" long, it provides 3.25" of travel for balancing your camera.
The 1/4"-20 camera tie-down screw inserts through a sliding assembly that includes the locating pin. The assembly offers you two positions for mounting the 1/4"-20 tie-down screw. The included 3/8"-16 tie-down screw attaches to the plate via its own designated mounting slot behind the 1/4"-20 sliding assembly. The rubber pads on the plate prevent slipping or twisting once your camera or camcorder is mounted on the plate. If you're using multiple cameras or switching from a camcorder to a DSLR, attaching a quick release plate to all your cameras makes swapping quick and effortless.