All Master Lock products are built with the unmatched strength and durability that you’ve come to know and trust. Each lock is individually tested to ensure years of trouble-free operation, dependable performance and peace of mind. Built-in Locker Locks feature: concealed mounting and rugged steel case to deter vandalism; key override for supervisory access (optional); automatic locking bolt or manual locking deadbolt model options; over a 10-year product life.