SMALLRIG Tripod Mounting Kit Weight Balance Mounting Plate for Accessories Attachment Follow Focus, Matte Box, etc - 1595 Tripod Mounting Kit 1595 includes 2pcs 15mm railblock and 2pcs plate. Used for long length, front heavy, camera packages. Attach it to the tripod plate with a 3/8''-16 screw and 1/4''-20 screw, then you can mount your dovetail baseplate on it. It clamps 15mm rails for accessories attachment, such asd follow focus, matte box, etc. The adjustability makes it possible to balance a front heavy camera on your tripod properly.