Padlock is a common portable mechanical locking device, its core function is to achieve physical closure and protection through the combination of the lock beam (U-shaped or straight rod-shaped) and the lock body. Lock body: the internal contains lock cylinder, spring, latch and other mechanical components, is the core control unit of the padlock. Lock beam (U-shaped rod): usually made of metal, can be inserted into the lock body to achieve closure. Part of the padlock lock beam can be retracted or disassembled. Lock cylinder: divided into mechanical lock cylinder (such as bullet locks, leaf locks) and electronic lock cylinder (such as password locks, fingerprint locks), to control the lock beam lock and release.