PERSONAL ATTACK ALARMS, Mini Gas Alarm, Each

Has a lock down head so that when operated it will sound continuously until the gas runs out. No batteries required. More than 4 minutes continuous sound output or 200 intermittent bursts. Fits easily into a handbag or pocket. 115+ dB (at 1 metre). Always armed, no on/off switch. Works at sub zero temperatures, down to -10 DegreesC. 10 x 3.5cm diameter.