Brand new and high quality Features: The 12V dual WiFi relay module uses ESP-01 as a WiFi module and is designed for 8-bit MCU chip. Only a simple configuration process can realize wireless control of 2-way relay via mobile app. Built-in ESP-01 WiFi module and high-performance microprocessor STM8S103. Module has 2 working modes: Mode 1: The phone is directly installed on the WiFi module. Mode 2: Equipped with a mobile phone and WiFi module on the router Additional Features: It can also be used as a USB relay when the ESP-01 is pulled out. Transmission Distance: In an open environment, when the mobile phone is installed on the WiFi module, the maximum stable transmission distance is 100M. When the WiFi module and the mobile phone are simultaneously carried on the router, the transmission distance depends on the router's signal strength. Built-in 12V, 10A // 250V AC 10A // 30V for DC relay, which can continuously pull 100,000 times, with diode discharge for protection and short response time. Uses Smartcongig technology to complete the account and password configuration on the APP ESP-01 WiFi module on the mobile phone and configure the username and password memory functions. Card mode selection and real-time indicator of working status. Reserved UART debugging interface and STM8 SWIM program download interface. Tips: Only for Android, IOS system cannot be used. Specification: Dimensions: 6x6.3cm/2.36x2.48inch Color: As shown Quantity: 1 pc Note: 1. Please allow 0-1cm error due to manual measurement. Make sure you don't mind before bidding. 2. Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1 x ESP8266 & ESP-01 4 Channel WiFi Relay Module