iiMash Mini USB RS232 Bluetooth Serial Adapter Communication Master-Slave 2 Modes 5v (Blue) transmit power 4 dbm receiving sensitivity -79dbm operating voltage 5v sleep current operating current 40ma1.6ma ( typical value) operating temperature storage temperature -10-50  c -20-80 degrees celsius size : 56.5mm x 38.5mm x 14.5mm