The Fox 40 whistle is the multi-purpose signalling device that is small enough to attach to everyday keys, marine or other outdoor gear. It needs no batteries, no fuel, and it's always on duty. No wonder it's used by rescue professionals worldwide! Classic is the standard choice referees and coaches at all levels, rescue professionals and general safety worldwide The harder you blow, the louder the sound No moving parts to freeze, jam or deteriorate 3-chamber pealess Sound Power: 115 dB