Handle and Cranking Lever Folds. No Power Supply Required. Compact for Portability. Powerful Universally Recognized Sound. Manual Hand Crank Operated Air Raid Siren. Produces a loud adjustable sound of 110 decibels. Made out of durable aluminium alloy. Perfect for peoples attention, or rooting for your favorite team in sporting events, and many more applications. By manually rotating the handle, the gearbox of the transmission acceleration to achieve the of sound, the sound depends on the rotation speed of the handle. Operation: manual hand lever operated Sound output: 1102(dB) Audio frequency: 55020(HZ) Transmission distance: 1000(m) Colour:Red Material:Aluminum alloy Package Contents: 1 x Hand Crank Siren Horn Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.