This UHPPOTE Electric Fail Secure Strike Lock & Round Cylindrica Knob Lock is the perfect solution for your security needs. It has a holding force of 500kg/1100 pounds and is suitable for door thicknesses of 35-50mm (1-3/8" to 2"). It is fail secure, meaning it is locked when power is removed, and is suitable for room doors and all kinds of wooden doors. It is a solenoid with one function and two contacts, with no polarity requirement. The lock will have polarity when a diode is added. This lock is easy to install and provides reliable security for your home or business.