Usage: Telecommunication Voltage: 5V Power Source: DC : bluetooth relay LC 12V Bluetooth 4-channel relay module equip with SPP-C Bluetooth 2.1 slave module and 8 bit high performance MCU, you can control the relay with cellphone APP directly. Protect Feature: Epoxy Contact Load: Low Power Model Number: bluetooth relay module The function and characteristics: 1, On-board N76E003/STM8S003 and SPP-C Bluetooth 2.1 module 2, The relay can be controlled with APP 3, Effective control distance(on open area): 10m 4, Power supply: 12V 5, On-board 12V, 10 A / 250 v AC 10 A / 30 v DC relay, absorb 100000 times continuously, Module with diode effusion protection, short response time 6, On-board optocoupler isolation components, anti-interference ability is strongly 7, On-board Bluetooth indicator and relay indicator LED 8, On-board preserved UART debug interface(Baud rate is 9600) and MCU program interface Interface: IN+, IN-: 12V power input TX, RX: UART communication SWIM, NRST: MCU program interface LED D2/D3/D4/D5(red): Relay indicator LED D1(blue): Bluetooth state indicator, the description of D1 as below: (1)It's means wait for establishing connection with the APP when D1 blink slowly (2)It's means the Bluetooth connect with the APP successfully when D1 on all the time colour:blue Material:PCB size:62.7*63.2mm Package Contents: 1 * 12V 4CH Remote Control Switch Module Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.