The Firefly II ADSU (Automatic Distress Signalling Unit) is a battery operated, compact personal alarm that automatically signals for help if the wearer becomes disabled. Weighing only 200 grammes, including battery, it uses advanced electronic technology to provide the most reliable protection available.The unit virtually eliminates false alarms, because it features a patented motion sensor that easily distinguishes between minimal wearer motion and no motion at all. Suited for applications where wearers are likely to remain relatively still for an extended period of time
