Function: 1. Manual alarm, easy to operate, just turn the handle to turn on the alarm. 2. The sound of the portable handheld siren was so loud that it could be heard from 1/4 mile away. 3. The housing is made of durable metal for maximum strength and durability. 4. Widely used in factories, schools, troops, natural disasters and coast guard, etc. can effectively provide timely warnings during incidents. 5. Small size, easy to carry and store, convenient to use and good performance. Specification: Item Type: Hand Crank Siren Type of operation: manually operated Sound Type: Siren Construction: metal housing Size: Width: approx. 5,51 inches Height: approx. 9,09 inch Depth: approx. 7.95 inches Decibels: 120 dB Size: about 11cm/4,3inch 23 cm / 9,1 inch Product Description: 1. A portable alarm is a handheld sounder that does not require power. It is called differently because of local differences. 2. Including the handle, gear speed booster mechanism, slider, fixed wheel, ringing wheel, sound window cover, gearbox, gearbox frame, handle is connected to the transmission speed booster drive shaft and gear output shaft, the booster mechanism passes through the pin is connected to the sliding block, and the sliding block is connected to the rotor flange by friction transfer. 3. There is no need for power, and the power is provided by shaking the handle so that the alarm sends 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 manual alarm and portable manual alarm. 5. The manual alarm is lightweight, easy to carry, can be detached, and the handle will trigger the alarm. 6. Widely used in factories, schools, branches, special flood protection, natural disasters, open barracks, air defense and other emergency situations. 7. It can effectively provide early warning during an incident and reduce property losses and victims. List of packages: 1 x Hand Crank Siren