Features: 1Remote Control: This GSM door opener with remote on/off switch can be used to authorize calls for free calls and can be operated from anywhere regardless of distance. 2Compact and Portable Design: The smart relay switch is designed for both portability and ease of use. Its compact design makes it ideal for use in everywhere. 3Wide Application: It can be used in industrial control and security fields such as lights motors remote controls wireless security alarms wireless access alarms wireless controllers etc. 4Smart Control: The smart relay switch is designed to work with smart home devices allowing for voice control and integration with other smart home platforms. 5Versatile Voltage Support: The Smart Relay Switch supports voltage inputs ranging from making it compatible with a wide range of electronic devices. Specification: Item Type:Relay SwitchPlug: European Plug 100-240v4G Frequency: B1 / B3 / B5 / B7 / B8 / B20GSM Frequency: 900 / 1800MhzSIM Interface: Standard SMA InterfaceOutput: Normally Open and Normally Closed Package List: 1 xRelay Switch1 xManual1 x Signal Receiving Line1 x Plug