A combination lock is a type of locking mechanism that requires a specific sequence of numbers or symbols to open. Unlike traditional locks that use keys, combination locks rely on a dial or a series of buttons. When the correct combination is entered, the internal mechanism releases, allowing the lock to open. These locks are commonly used on lockers, safes, and doors. Combination locks can be either mechanical or electronic. Mechanical locks use gears and tumblers, while electronic locks may use keypads or touchscreens. Both types provide security and are popular for their convenience, as they eliminate the need to carry a physical key.