SPP-C Bluetooth to serial port adapter module set replaces HC-05/06 slave machine with base plate JDY-31. 

SPP-C Replace HC-06 Bluetooth Serial Pass-Through Module SPPC Wireless Serial Communication PCB Bluetooth Module For Arduino , BK3231 Bluetooth Module is compatible with HC-05/06 slave mode, support Bluetooth SPP protocol, transmission speed up to dozens of K per second, can replace the Bluetooth 3 and 2 serial communication module on the market. Product Parameter：

Working Voltage: 2.2-4.2V Working Temperature：-40~85 Degree Celsius Antenna： PCB on- board antenna Wake Mode：19MA Sleep Mode: 40uA