Disable the Door Knob/Faucet/Valve The device is made of stainless steel. It is designed to cover and lock around your door knob and prevent your knob from turning by locking-out access to the knob and keyhole.Applicable to Most Standard Door Knob/Handwheel - Fits round, tulip and oval door knobs, not to lever door handles. Suitable for faucet/tank with handwheel valve.What It for - It can be used on the exterior or interior side of the knob. Case 1: When going out, you can use this device to lock the knob to add security. Case 2: When you're at home or hotel, like sleeping, you can use this device to lock the exterior knob to add security. Case3: Prevent someone, such as people with dementia, from wandering out of the house. Case 4: Prevent child from operating the door knob/handwheel and prevent mis-operation.Easy to Install, Carry and Store Just place the device over the door knob, lock and go. The device is built handy size. A pouch is included in package. With this pouch, the device can be stored and hung on the door handle or door stopper for easy access.