The Petersham 20mm set is a must-have for sports referees and coaches. This set includes a sturdy ring to hold important items together and a reliable referee whistle for clear communication on the field. The 20mm width provides durability and ensures long-lasting use. Stay organized and prepared during games or practices with this convenient set. Whether you're officiating a game or leading a team, the Petersham 20mm set will help you stay on top of your game.