The Model # 8308 is a single tone electronic whistle. Loud, Consistent Sound Every Time, even if user is short of breath or injured. Personal Safety & Signaling Device – for Hikers, Hunters, Campers, Senior Citizens, Joggers, School Teachers, Boy Scouts/Girl Scouts, Security Guards and anyone who could benefit from carrying a whistle. Referees and Coaches – Easier to give verbal commands without a Whistle in user’s mouth, yet with Whistle sound always “at the ready” to stop play or practice. Each set of AAA Batteries produces more than 1000 blasts. Loud 105-dB Whistle sound can be aimed in the exact direction intended, and away from user. Improved Hygiene – Hand operated instead of mouth blown is sanitary, even for multi users.