Features Piezo Dynamic Technology that delivers powerful performance while significantly reducing weight and increasing battery life. Full frequency response provides clear intelligible amplification. Adjustable volume and three modes (talk siren and whistle) offer enhanced versatility. Battery indicator light vividly shows power status. Weatherproof design stands up to inclement weather. Pistol grip and wrist strap make it comfortable to hold. Audio Range: 0.62 mi; Diameter: 7.75 ; Length: 12 ; Maximum Battery Operation Time: 18 h.