The LOCKEYUSA 3830 Double Combination Satin chrome Marine Grade is a commercial digital mechanical push button knob door or gate lock (gate boxes sold separately). The 3830 fits doors or gates that are 1-1/8 in. to 2 in. T and can go up to 5 in. T with an extension kit (sold separately). Included in the 3830 are rubber trim plates that will protect the lock from the elements. From the outside, the lock is opened with an easily customizable 2 to 5-digit user code with a lever. The outside lock body can be set into a passage function that allows the lock to be unlocked until disabled. From the inside, the lock is free passage opened with a knob. Adjustable for a 2-3/8 in. or 2-3/4 in. backset. The 3830 is completely mechanical with zero batteries and zero electrical wiring involved. The 3830 provides high durability, along with trusted security and LOCKEYUSA stands by that by offering a Lifetime Mechanical warranty.