This alarm is great for any door, whether it be in your home, at the office, away on travel or staying in a dorm. When pressure on afore mentioned door is applied, the extremely loud (120 dB Siren) helps wake/alert homeowner, renter or user of intruder’s attempted entrance. It can also alert neighbors of unauthorized intruders! Also as an extra level of security which provides battery status update with low battery indicator. [Uses a 9volt battery- Not Included]