Product Brand new Material: aluminum alloy Red color Dimensions (approx.): Length: 115mm Width: 202mm Height: 9.1 " Operation: hand lever operated Sound output: 110 2 (dB) Audio frequency: 550 20 (HZ) Transmission distance: 1000 (m) Handle and crank lever folds. No power supply required. Compact for portability. Quantity: 1 piece Delivery content: 1 x air alarm 1. The hand siren crank does not require a power supply Manual air raid siren with winch drive. Produces a loud demodulated sound of 110 decibels. By manually turning the handle, the gear will gradually accelerate the gear for sound purposes, and the sound will depend on the speed of the handle. 2. Compact and portable hand crank siren The handle and lever are folded for easy carrying over the supplied hip pouch. Made of durable aluminum alloy. Strong, widely recognized voice. 3. Great for getting people's attention or searching for your favorite team through sporting events and other apps. 4. This hand operated light siren produces 110 decibels This is a powerful, adjustable sound that draws attention to refugee camps and schools, and whether you are cheering or your favorite team at a local sports game. You need to listen to a valid warning. 5. By manually rotating the handle the gear of the gearbox step by step acceleration, in order to achieve the purpose of the sound, the sound depends on the speed of the handle.