Parallel drafting arm with double-sided scale. Convenient single-handed double locking mechanism for setting any position on the rail. Twin rail for especially smooth, even gliding of the ruler. Colour indicator shows whether locked or unlocked. Sheet clamping strips on both sides of the drawing board for fastening of paper - securely holds more than one sheet at a time. Scale with needle hole for precise compass radius setting.Made out of sturdy, break-resistant plastic, with non-slip rubber feet.