The Manfrotto 509PLONG Quick Release Plate for 509HD Head is an extra-long 5.5" plate for video cameras. It's compatible with the 509HD head, as well as other newer Manfrotto video heads. The plate includes a 1/4"-20 screw and a 3/8"-16 adapter for compatibility with virtually all video cameras. The 509PLONG plate works with Manfrotto's Advanced Balancing Recorder (ABR) system.