Specifications:This siren is featured with manual operation design and it is portable so it is very easy to carry.Handheld alarm siren is used for factories, families, schools, flood control, disaster relief, public and industrial occasions.By manually rotating the handle so the gearbox of the transmission step by step acceleration to achieve the purpose of sound.The sound depends on the rotation speed of the handle.It is made of durable aluminium alloy that is more sturdy and wear resistant.This hand alarm can be warning timely to reduce the loss of people& 39;s property and casualties.Item Name: Handheld Alarm SirenMaterial: Aluminum AlloySound Rating: 1102dB(A) @1mFrequency: 55020Hz (Dependent on Rotation Speed)Effective Range: 1000mSize: 20.2cm x 23.1cm x 11.5cm/7.95" x 9.09" x 4.53" (Approx.)Notes:Due to the light and screen setting difference, the item& 39;s color may be slightly different from the pictures.Please allow slight dimension difference due to different manual measurement.Package Includes:1 x Handheld Alarm Siren