Beeper Dogra RB-1002. High audibility at a great distance
pologar > Dogtra 2500 T&B Training and Beeper
Amazon.com: Dogtra 2700 T&B 1-Dog Remote Training and Beeper Collar - 1 Mile Range, Fully Waterproof, Rechargeable, Static, Vibration - Includes PetsTEK Dog Training Clicker : Pet Supplies