Referee Whistle Pouches & Shields
All protective referee whistle pouches & shields are approved by the NCAA (and other groups) to attach to your whistle and limit particles emitted toward players & coaches.
The difference between a pouch and a shield are that pouches particles and shields divert, with maximizing sound. While both should be cleaned after each use, the shield is easier by simply wiping it clean whereas a pouch should be washed with soap and water.