The Fox 40 Caul is a specialized pealess whistle featuring an integrated flexible fingergrip that fits securely for hands-free use. Its unique design produces a lower-toned, traditional trill that cuts through crowd noise without the high-pitched shriek of other models. Constructed with a Cushioned Mouth Grip (CMG), it provides superior comfort and tooth protection during intense officiating. The whistle is specifically engineered for cold weather environments, ensuring it won't freeze or fail in freezing temperatures. Because it has no moving parts to jam, it remains a highly reliable and durable choice for professional referees and coaches.