Shenzhen Waytronic Electronics Co., Ltd MicroSound V15.161MicroSound(Door Magnetic Induction)V15.161. Product features Door magnetic induction triggers to play voice; induction distance is 2 cm. Adopt WT2003 voice chip; welcome mode and alarm mode are alternative(trigger to play the first voiceregularly). A button is to choose the next one and switch between A and B mode; B button is to adjust volume andswitch mode between trigger with interruption and trigger without interruption. A mode is all loop play; B mode is single playback. Power-off memory mode; default mode is B mode, trigger with interruption. Through PC software, direct to update voice by USB cable connected to computer. Adopt 3 AAA batteries or USB to supply power, choosing only one power supply mode. When downloadvoice, take out the batteries first, then connect with computer to replace voice. Built-in 8 ohm 1w speaker.