Crime Prevention Buzzer
1
A pocket-sized device designed to emit a loud, alarm-like noise when activated.
A Crime Prevention Buzzer (防犯ブザー bōhan buzā) is a device designed to emit a loud alarm noise when activated. It primarily has the shape of a small casket with a single button used to activate the device.
As it literally translates, the device is designed to deter any would-be criminals by making a loud noise. The sudden noise and siren-like sound can have an effect on a assailant by either disorienting them or startling them.
A similar English word would be "personal alarm", a generalized term.
General purpose
Professional
Asashio-class (Kantai Collection); A badge-sized searchlight is being used on the design of Kai Ni (power-up form), but its shape and equipment position has been commented of it looking like a crime prevention buzzer.