Microchip RN42XVU-I/RM Bluetooth Chip 2.1, Bluetooth Class: Class 2, Maximum Output Power: 4dBm, Receiver Sensitivity: -86dBm, Supported Bus Interfaces: UART, Supported I/O Interfaces: USB, Dimensions: 29 x 24.4mm, Length: 29mm, Maximum Operating Temperature: +85 °C, Minimum Operating Temperature: -40 °C.