The lock products are widely used in industrial facilities, cabinets and other closed structure for locking the door. In the process of locking the door, it also might provide a strong pulling force, compressing the seal on the edge of the door plate to act as a seal. The lock has Poke-Yoke design concept, in the case of the lock is not properly closed, its protective cover cannot be covered normally; We can determine whether the lock is properly closed by the fluorescent film on the visual protective cover.