ABS material, 130dB Self Defense Security Alarm Keychain. Comes with two 3A batteries. When in danger, the emergency siren sounds loudly to attract attention and protect you from an emergency. Everyone's personal alarm can maximize your personal safety and security anytime, anywhere, and provide a perfect defense mechanism for students, the elderly, children, women, joggers, night shift workers, etc. It is a good choice as a gift for friends, parents, lovers, children. 3 3/8" L x 1 3/16H