The Rock-N-Roller Quick Set Shelf is designed to quickly and seamlessly transform your R8, R10, or R12 cart into a mobile workstation. Once the 4 support tubes are installed, the shelf sets up and comes apart in seconds, and can be stored with the support tubes installed, making on-site assembly and disassembly quick and easy. The surface measures 16" wide, and can be configured at a short 32" length or a full 50" length, to provide ample work space for Mobile Sound, Film Production, Testing Equipment, and other professional on-site applications, as well as maximizing gear transport efficiency. The shelf is 0.5" thick, supported by steel tubes, and covered in heavy duty textured paint for extra durability. Maximum recommended weight capacity is 150lbs. Shelf kit includes shelf, 4 support tubes, and 4 mounting bolts.