Deadbolt. This lock type is considered to be the most secure one. These locks are sturdy and really hard to break. They can be single-cylinder or double-cylinder.

Typically the sweethearts' names or initials, and perhaps the date, are inscribed on the padlock, and its key is thrown away (often into a nearby river) to symbolize unbreakable love.

3 star cylinder locks are designed with anti-pick mechanisms, making it incredibly difficult for even the most skilled lock picker to manipulate the pins successfully.

A pick-proof lock is a lock with specialized keys and safety features that prevent lock picking and bumping. The best pick-resistant locks to buy are the Medeco3 Cam Lock, BiLock deadbolts, and the EVVA MCS locking system.