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 users mouth, yet with Whistle sound always “at the ready” to stop play or practice. Each set of the included 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.