|These single lock drawing boards are of an ergonomic design for easy, comfortable working. They have a parallel drafting ruler with double-sided scale, A single Stop-and-Go locking system to lock the drafting ruler any position on the guide way. Featuring a guide way for smooth and easy to move positioning of the drafting ruler. Single sided paper clamp to fix or loosen the paper. These drawing boards are made of high-impact plastic material making them light weight and extra stable.