YL-333 Magnetic Anti-theft Alarm is a simple Plug and Play security Alarm system. It is two AAA battery-operated Alarm system that works on magnetic touch. This Alarm produces a very loud alarm sound (90dB) that will ideally protect against an unwanted intruder or facilitate the work of a guard. YL-333 Magnetic Anti-theft Alarm system is a portable and economical device for multipurpose use. Working Principle: It starts producing sound when the small part detaches from the main unit and stops alarming when reattached to each other. The module has an On-Off switch to make it function whenever required. This Security System can be easily installed and no wiring required and hence can’t be stopped easily by an unknown person when started.