Main Crank Horn Siren Portable 110dB Manually Operated Metal Alarm Air Raid Emergency Security Alarm

By manually turning the handle, the transmission gearbox accelerates step by step to reach the desired sound; the sound level depends on the handle's rotation speed. Timely Warning, Reduces Loss of People's Property and Casualties Can be used in factories, homes, schools, for flood control, disaster relief, and at public and industrial events. It is used for emergency warnings and is easy to transport. Made of durable aluminum alloy, strong and wear-resistant.