This is new Hejnar Photo Quick Release 8.00 inch rail with 2.375 inch clamp. Something similar to rail with integrated clamp after assembled. Great as nodal slide. I do provide 2 dowel pins with rail. It prevent clamp from twisting. Clamp itself is 2.375 inch with dual mounting and captive style knob. Clamp can be place on rail with knob facing back or side. It is the best quick release system for tripods and monopods when combined with Arca style ball head and quick release clamps. International standard dove-tail rail, compatible with Arca-Swiss type quick release clamps