◆Small receiver, red indicator light blinks with loud beep prompting, can last 15 seconds(Or press Cancel) ◆Small-sized, exquisite. With two buttons ‘Initialize’ and ’ Register/Cancel ◆Please note that the receiver need to connect with power adapter(included in the package), do not use battery. ◆Size: 3.4*1.7*0.6 in (86mm * 43mm * 15mm) ◆Use a Power Supply Adapter