1. USB rechargeable The personal alarm siren consists of a rechargeable lithium battery and not a button battery.2. Loud warning 130dB piercing siren is enough to attract attention and unsettle the attacker. Up to 60 minutes of continuous tone for emergencies. It replaces self-defense weapons to protect your safety.3. Two ways to use You can pull out the contact pin or press the switch twice quickly to activate the alarm.4. LED flashlight Integrated LED flashlight to illuminate dark sidewalks or to find keyholes.5. Lightweight and Portable: With double buckle design, it can be attached to backpack, school bag, belt loops, suitcase or key chain, etc. Perfect emergency self-protection for students, women, night joggers and night workers.