1Handheld alarm, easy to operate, just turn the handle to sound the alarm. 2The sound of the portable manual siren was so loudly that it could be heard from 1/4 mile away. 3The housing is made of durable plastic for maximum strength and durability. 4Widely used in factories, schools, troops, natural disasters and seaside guards, etc. can effectively provide timely warnings during incidents. 5With small size, easy to carry and store, convenient to use and with good performance. Item Type: Hand Crank SirenOperation Type: Hand OperatedSound Type: SirenConstruction: ABS Plastic HousingSize: Width: Approx. 5.51in Height: Approx. 9.09in Depth: Approx. 7.95inDecibel: 120dbSize: Approx.11cm / 4.3in23cm / 9.1inProduct Description: 1. The portable alarm is a hand-cranked sounder that does not require power support. It is called differently due to local differences.2. Including handle, gear speed increasing mechanism, slider, fixed wheel, ringing wheel, sound window cover, gear box, box frame, the handle is connected with the driving shaft of the gear speed increasing mechanism, and the output shaft of the gear increasing mechanism passes through The pin is connected with the sliding block, and the sliding block is connected with the flange of the impeller by friction transmission.3. There is no need for power support, and the power is provided by shaking the handle to make the alarm send out an alarm signal. The sound level depends on the speed of the hand.4. In terms of style and purpose, it is divided into fixed hand-operated alarm and portable hand-operated alarm.5. Hand-cranked alarm is light in weight, easy to carry, can be detached, and the handle will sound an alarm.6. Widely used in factories, schools, troops, special flood control, natural disasters, open barracks, air defense and other emergencies.7. Can effectively provide timely early warning during the incident and reduce people's property losses and casualties. 1 x Hand Crank Siren