These optical rail carriers are in good condition with cosmetic wear (mostly scratches) along the top portion of the carriers. They contain a center bore with 16M threads, and 2 M6 thread holes on both sides of the bore. You can lock in the rail using a knob that steadily pulls the carrier into place (has 7mm travel). The carrier is 90mm x 65mm x 27mm ( L x W x H ).

The Rail Carriers may be quickly lifted and set again on a rail. Slide the carrier to any point on the rail and secure it with the fixing screw. The carriers have patterns of M6 and Ø6.4 mm mounting holes used to fasten other units. It has a Ø18 mm clear aperture. 

Precision Carriers come in two widths: 25 mm and 50 mm. Carrier may be used as a reference for repeated positioning. Units, may be reinserted exactly into the same position next to the reference carrier. Rail Carriers are made of black finished hardened steel.