SmallRig Tripod Mounting Kit W/15mm Rail Block 1798is combined by two SmallRig Tripod mounting plate w/15mm rail block. 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 base plate on it. It clamps onto 15mm rails for accessories attachment, such as follow focus, matte box, etc. The 40mm groove makes it possible to balance a front heavy camera on your tripod properly.Key Features:1. Attach to any tripod plate or other standard bridge plate2. Clamps onto 15mm rails for accessories attachment3. Allows 40mm adjustment for balance controlPackage Includes:2x Base Plate2x 15mm Rail Block 8401x 1/4''-20 Screw1x 3/8''-16 Screw1x SpannerProduct Dimensions: 90x110x40mmNet Weight: 380g Key Features:1. Attaches to any tripod plate or other standard plate2. Clamps onto 15mm rails for attaching accessories3. Allows 40mm offset for balance controlPackage includes:2x base plate2x 15mm rail block 8401x 1/4''-20 screw1x screw 3/8''-161x wrench.Product dimensions: 90x110x40mmWeight: 380g