The MPR-73-3/8 is a multi-purpose rail that can be used as a camera body plate for some medium and large format cameras, or as a lens plate for any object with a 3/8" socket. An optional MPR-C flange cane be installed in 3 different positions to prevent twisting and has a 1.42" slot length for adjustability. Really Right Stuff Multi-Purpose Double Dovetail 2.9"/73mm Rail w/(1) 3/8"-16 Mounting Screw RRS-9000448 in Black