Features: It can effectively fix plates, keep right angles, and assist in plate connection and shaping. With adjustable fixed block, it is suitable for different kinds of thickness plates and has a wide ranges of application. The square has accurate scale and multiple angle measurement, which is convenient for operation and design. ABS plastics material, safer to use, light and portable, will not damage the plate. Two packs, four packs optional, can meet most of the needs of users.