The Acme No. 660 Thunderer Whistle is possibly the biggest selling whistle of all time. Easy to blow, small, high pitch and loud (117dBA), the 660 Thunderer is favoured by customers in colder settings where metal might stick to the skin. Also chosen by officials in sports, teaching, animal training, police authorities, military units, and music specialists. - Small and lightweight yet durable - Tapered mouthpiece for comfort - Produces a high pitch, large sound that cuts through other noise to be easily heard and works well in games - Made from BPA Free Plastic to Food Grade Standard - Ideal for sports, gym classes, in teaching, as a coaching whistle, for dog training, as a safety whistle, for walkers and ramblers, and more - Attention grabbing Part of The Acme range of high quality whistles made in the UK by specialists with over 150 years of experience sold here on Amazon. Check out THE ACME store for more.