Years of proprietary research and development have resulted in a one-of-a-kind all-encompassing whistle and fingergrip. Named The Caul in honor of the late John McCauley, former NHL Referee and Director of Officiating. Strong polycarbonate body Integrated over-mold CMG technology Dual-chamber pealess technology Sleek design Highly-durable yet flexible rubber form-fitting fingergrip Pealess-style whistle doesn't compromise the traditional harmonized trill tone Crisp loud sound and extremely easy to blow Sound Power: 110 dB Fox 40 Caul Fingergrip Whistle, Black MS1219224 MS1219224 66143070003