Features: Use a mobile phone to make a call or send a message to this GSM socket to switch the power socket on or off, allowing control of electrical appliances Works in any location where GSM signal is available Supports setting up to 5 master phone numbers Can control water heaters, electric motors, electric doors, lights, rice cookers, and other appliances Note: 1. Controls only the on/off function of the power supply; no additional functions are supported 2. Can work directly with standard electrical appliances; for other controlled devices or button-operated appliances, only those with memory function are compatible 3. SIM card requirements: A global GSM standard SIM card is required; 3G or CDMA cards are not supported. Activate the SIM card before inserting it into the device 4. It is recommended to use a SIM card with free incoming calls to minimize costs; only SMS fees will apply 5. Caller ID must be enabled, and the SIM card must have sufficient balance to receive calls and messages 6. Do not install the GSM switch in a metal enclosure or enclosed metal environment 7. In areas with weak signal strength, SMS control may be less reliable; this is normal operation Specifications: Voltage: 110V-220V Current: 10A Rated frequency: 50Hz Power: 2200W Plug Type: UK/EU Plug Size: 100x65mm / 3.94x2.56 inches Quantity: 1 Piece Note: Please allow 1-3mm variation due to manual measurement. Ensure you are comfortable with this before purchasing Due to differences in monitor displays, the actual color of the item may vary from the image. Thank you! Package Contents: 1 x GSM Switch 1 x User Manual