Homya&reg; Dog Training Whistles for Control Barking Teach Commands Sit Stay Fits Right on Your Keychain Farthest Reaction Distance Training Repellent for Dogs Pigeon Eagle Dog Training Whistle UltraSonic Sound Ultra Sonic IT IS NOT SILENT it does emit a sound, that your dog can hear from far distances A great tool to have to train your pet; small and easy using; Train your dog to Sit down,Jump and so on Dogs hear whistle from up to 20000 inch away (direction and strength of wind may affect the distance); Call your dog to Come back even it is far from you Great for Hunting Dogs, Stubborn Dogs. Far away from the bark of a dog; Ideal for summoning your pet