100% brand new and high quality Features: Widely used. Stable performance. Maximum operating current: 15A. The operation is simple and easy to understand. According to requirements, there are two options available. Specifications: MCU: ESP32-Wrover-B FLASH: 4MB PS RAM: 8MB Communication protocol: UART SPl ... l2C ... can l2S ... SDIO Wireless protocol: Wi-Fi: 802.11 b / g / n Bluetooth-Compatible : V4.2 BR / EDR and BLE Built-in functions: four groups of relays, optocoupler isolation, 16 expansion IOs. HRS4H-S-DC5V relay: standard power consumption: 360 to 450 mw 1 K1 relay: I021 2, relay K2: four blue LEDs I019 3 K3 relay: I018 4. Relay K4: I005 relay operation indicator Maximum response / release time: 8ms / 5ms Maximum operating current: 15A External power supply voltage input range: DC 12 ~ 24V Working temperature: -40 ~ 80 Support T-U2T downloader: It can be connected to use T-U2T USB to serial downloader, which is convenient, fast, safe and beautiful. Can also be powered directly by USB Type-C Note: Since the motherboard does not burn or discharge chips, this product needs to use the T-U2T automatic downloader to load the program. If you dont have a T-U2T, you have to buy the corresponding version before loading the program. If you already have a T-U2T, you only need a T-U2T automatic unloader to be compatible with T-U2T series products, no need to repeat the purchase. Due to the monitor difference and light effect, the actual color of the item may be slightly different from the color shown on the pictures. Thanks Please allow 1-2cm measuring deviation due to manual measurement. Package Includes: 1 X four way T relay 2 X pin header or 1 X Four Way T Relay 1 X T-U2T Discharger 2 X Pin Header