SOLID CONSTRUCTION: Made of intensive aluminum alloy, Lightweight for mobile film-making, suitable for long-hour continuous work. Rail hole diameter: 15 mm/0.59inch. Rails c-to-c distance: 60mm/2.37inch. DESIGN: Customized design for adding/replacing component(s) in some specialized occasions for film-making. Ergonomically design shoulder pad, more comfortable. The rail rod can be disassembled. STABLE: To provide you with a stable and accurate video capture platform, adds a level meter. In accordance with international standards, and can be installed 15mm rails (tube diameter 15mm /0.59inch center distance 60mm/2.37inch), twin-tube more COMPATIBILITY: Can be installed with video-capture series of related accessories. Suitable for 1/4 'screw-holes and 3/8 'screw hole of digital SLR cameras and camcorders. Can be fixed in the camera tripod shooting.