Low-cost
door alarm.
This door alarm is a low-cost, effective way to alert attendant to
a wandering resident. A switch that looks like thin, flexible
tweezers is inserted between door and doorjamb. When door is
opened, tweezers' arms separate activating the alarm. Excellent
for home use - loud alarm can be heard from a distance. 110dB.
Uses one 9-Volt battery (included).