KEYESTUDIO Bluetooth Module (HM-10 Bluetooth-4.0 V2) for Arduino keyestudio HM-10 Bluetooth-4.0 V2 adopts TI CC2541 chip and configuration space of 256Kb. It supports AT command. Users can modify working mode (master/slave), baud rate, device name, paring password etc. Bluetooth protocol: Bluetooth Specification V4.0 BLE No byte limit in serial port Transceiving In open environment, realize 100m ultra-distance communication with iphone4s