Specifications: JAMTON ultra slim siren speaker can reach a high volume of 130 dB, and a Impedance of 8 ohms. | Easily Compatible: Capable with all 100-200w alarm systems, speakers can be used directly when connected to the alarm controller. Fit for police cars, ambulances, fire engines, trucks, cars, SUVs, engineering vehicles, ATVs, UTVs or any other vehicle. | High Quality: Black heavy duty material, Equipped with mounting bracket and waterproof. The compact 5.7H x 5.7W body can be mounted in the engine compartment, as well as in other locations on the vehicle. | Package including:1 × 200W compact high-performance ultra-thin siren speaker (suitable for all 100-200W alarm systems). | Note: This speaker should be used with DC 12V / 8 Ohms resistance, otherwise it will not produce sound or sound low.