This is new Hejnar Photo Quick Release 4.00 inch rai with 1.0 inch clamp. Something similar to rail with integrated clamp after assembled.
I do provide 2 dowel pins with rail. They prevent clamp from twisting. Clamp itself is 1.0 inch wide with dual mounting and captive style knob. Hard coat black anodized surface. Works great as nodal slide. Clamp can be oriented on rail with knob behind rail or knob on rail side. Great addition for 4/3 cameras user shutting panorama