Company of Animals High Frequency Whistle for Dogs The Company of Animals High Frequency Whistle is a lightweight, compact, ‘silent’ whistle.. INDOOR & OUTDOOR TRAINING: The COA High Frequency Whistle is ideal for dog training, both indoors and out. SENSITIVE DOGS: The whistle is particularly appropriate for noise-sensitive breeds such as Border Collies. GREAT FOR LONG DISTANCE: Producing a sound that travels well in open spaces. ADJUSTABLE PITCH: The pitch is adjustable, so you can find the best pitch to suit your dog and it comes with a key ring attachment, to ensure the whistle is always to hand.