Gritech 120dB Wearable Emergency Personal Alarm Pendant with Keychain,the Wolf Alarm for Jogger,Kids,Student,Women 120dB Emergency/Attack Alarm with user replaceable1pc LR44 batteries 12V*23A (included) Emergency activation - simply pull the pin for up to 30 minutes of continuous piercing alarm Preferred for college security, police and correctional officers, walkers, joggers, elderly, night owls, lone workers, students, and self defense Lightweight and tranditional style makes it easy to take away. as a pendant with neck strap and as a keychain clips to your purse or on your handbag/backpack etc