FOX40 whistles never fail and cannot be overblown. The harder you blow, the louder the sound, which can be heard over a mile away, This faultless performance has made our whistles the preferred choice for proffesional and amateur sport federations, personal safety and rescue professionals worldwide. Newly patented two-chamber pea-less whistle, with low pitched tone, is a favorite with a multi-sport referees and coaches. Available in whole range of colours.