1、Remote 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. 2、Compact 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. 3、Wide 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. 4、Smart Control: The smart relay switch is designed to work with smart home devices, allowing for voice control and integration with other smart home platforms. 5、Versatile Voltage Support: The Smart Relay Switch supports voltage inputs ranging from , making it compatible with a wide range of electronic devices. Item Type: Relay Switch 4G Frequency: B1 / B3 / B5 / B7 / B8 / B20 GSM Frequency: 900 / 1800Mhz SIM Interface: Standard SMA Interface Output: Normally Open and Normally Closed 1 x Relay Switch 1 x Manual 1 x Signal Receiving Line 1 x Plug