Features: Wear resistant structure: Crafted from aluminum. Compose of a handle and internal mechanical device, it emit a high-frequency alarm when the handle rotates rapidly, effectively attracting attention in emergency situations. Small size and portable: easy to carry and operate, providing effective warnings in emergency situations, and extremely practical even in the absence of power. Adjustable volumes: The volumes can be adjusted according to the speed of the handle rotation. The faster the speed, the louder the sound, and can be opened to far enhances the sound effect. Alarm construction: adjustable volumes function, up to 110 decibels, and the hand cranked alarm emit clear and penetrating sound, with a wide transmission ranges and long service life. Widely used: Suitable for various emergency situations such as sudden fires, attacks, or emergencies, and can also be used as a personals tool. Its manual operation allows it to provide effective alarms without the need for battery. Specifications: Material: Aluminum Sound pressure level: 110DB Valid ranges: Diameter 1000m / 3280feet Color:Green,Red Size:Approx.198mm/7.8'x205mm/8.1' Package Includes: 1Piece Hand Crank Siren note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color.