Combination Padlocks

• Combination padlocks feature a numerical dial with which a preset combination is entered to disengage the locking mechanism. Many combination locks feature a single dial located on the face of the lock. This dial is spun in alternating directions to input the correct numerical combination. Other combination locks feature multiple dials in succession. Each dial is used to input a single digit of the combination. Once all of the dials are rotated to the correct number, the lock will disengage.
  
  

Key-Operated Padlocks

• Many padlocks are key-operated. These padlocks feature a keyhole somewhere on the lock body, which disengages the internal locking mechanism. Key-operated padlocks offer the benefit of quick disengagement, as compared to combination padlocks. The internal mechanisms of a key-operated padlock are also simpler in design than a combination padlock. Therefore, key-operated padlocks are often better suited for outside use, as they will better withstand weathering effects.
  
  

Shackle Types

• Most padlocks feature a U-shaped shackle that allows the lock to be hung from the object it is locked onto. The two different shackle designs are open shackles and closed shackles. Open shackle padlocks feature a bare shackle that protrudes fully from the lock body. This makes the lock versatile, as open shackles offer the most clearance possible. Other padlocks may feature a closed shackle type. Closed shackles are, for the most part, encased in the lock body when the lock is engaged. This makes for a sturdier padlock overall, but also limits the use of the padlock, as the closed shackle has less clearance than an open shackle.
  
  

Discus Padlocks

• Discus padlocks, also known as round-shackle padlocks, can offer a high level of security. Discus padlocks feature a perfectly round body, into which the shackle is built. When locked, the shackle completes the circle of the outer lock body, thus supplying a very secure lock. Since the locking mechanism in discus locks is not spring-operated, a quality discus lock will remain locked even if the lock body is severely damaged.