Features: The magnetic door alarm protects your safety and is suitable for various door and window locations such as home/school/factory/shopping mall/office building. It is sensitive and can synchronizes with mobile phones and computers. Made of flame-retardant Plastic+Metal material, the surface is delicate and smooth, moisture-proof and rust proof, sturdy and durable. Sealed design, dustproof and waterproof, even if the door sensor is in water, the signal will not be interrupted. When the door Magnetic Sensor is separated, a signal is immediately sent to the host. After receiving the signal, the host will alarm and push the alarm signal to the user. Punching installation. After setting the defense modes, when someone open a door or window (the door magnetic host is separated from the magnetic strip), an alarm notification will be immediately given and an alarm sound will be emitted. Specifications: Material: Plastic+Metal Current: 0.5A Sensing distance: 50-70mm/1.97-2.75inch Package Includes: 1 Set Sensor note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.