The lock is made of all metal and fully mechanical No power source or battery is needed and both water and heat/fire proof. Mutex Security MUTEX Mechanical Keyless Lock MX230G-D with Keypad & Mechanic Key Entry, Water & Heat/Fire Proof, Stainless Steel in Deadbolts Very reliable Fully mechanical, no battery or power sources are needed.Highly reliable. Adams Rite eForce-150 Powdercoat Dark Bronze Finish Keyless Entry... Blusafe Apollo Black Keyless Door Handle for Hoe Security, Finger... It has a keypad on both sides so it can secure the gate in and out. It is extremely reliable. Knox Box Fire Department Approved MUTEX Mechanical Keyless Lock MX230S With Keypad & Mechanic Key Entry Both Inside Outside Water Heat Fire Proof 100 Mechanical Very Reliable Double Sided Keypad Door Lock