Including installation hardware. Easy to install. An additional air system is required. Brand new speakers. The air horn is equipped with a stainless steel gas tank. The horn is suitable for all 12V/24V trucks, boats, cars, motorcycles, etc. Two speakers Maximum 175db, super loud. Specification: Material: stainless steel 304,Zinc chromium , ABS Bell mouth diameter: 89 mm/3.54 inches Length: 396 mm/15.75 inches Width: 200 mm/7.87 inches Height: 110 mm/4.33 inches Voltage: 12V 24V Volume: 175DB ± Weight: 1.86 kg 1. When installing, make sure that the horn is slightly inclined downward to prevent water or dirt from entering the horn and affecting the horn Effect. The maximum decibel of the product is 175DB. 2. Due to the effects of photography and light, the actual color may have chromatic aberration, which is slightly different from the picture;Due to manual measurement, please allow a deviation of 1-3 cm. If you want other styles of speakers, please search our store on Amazon.