The black anodized SSB-02 Index Stop Bar from Sunwayfoto is a CNC-machined aluminum clamp that is mountable on Arca-type rails, brackets, and plates. The clamp closes via a screw locking knob, and as a stop bar, it limits the movement on a rail or sets as an index point while shooting a panorama. A 1/4"-20 mounting socket is located on the back of the clamp for threaded accessories.