Durable, lightweight plastic instrument, designed for whiteboards/chalkboards. Made of white polystyrene and features handle for ease of use. 45 degrees triangle with a 23" base and 16"sides. Durable, lightweight plastic instrument, designed for whiteboards/chalkboards. Made of white polystyrene and features handle for ease of use. 45 degrees triangle with a 23" base and 16"sides.