The ALPHA is the most efficient whistle ever made. Its frequencies generated are now concentrated in the dog’s middle octave hearing range, enabling the dog to hear with more clarity. Its contemporary design encompasses a new comfort grip in the hand and mouth. You only have to breath into it for a quality sound enabling you to produce commands so quiet they are almost inaudible to people - perfect for close working dogs. The ALPHA is easier to use and produces a far greater variety of whistling sounds and styles so owners can communicate effectively with their dog, helping to maintain control. Specially designed to sound at a frequency of 5700Hz, the ACME 211½ ALPHA dog whistle can be heard by your dog at distances up to 1.5km depending on the weather conditions and terrain. The ACME 210½ ALPHA dog whistle sounds at a frequency of 6200Hz which is effective up to 90m under ideal conditions. Features: Enhanced performance and control of your commands. The Comfort Grip add stability in the hand in all weather conditions. Easier to blow due to a reduction in air loss, allowing for quieter sounding more responsive commands. Made in the UK using the most technologically advanced materials and production methods to create a World leading product.