AMERICA'S #1 BEST-SELLING TENNIS BALL: Penn Championship is the top choice for everyday players, clubs, and coaches - trusted for consistent quality, durability, and performance across all court types. DESIGNED FOR YOUNG BEGINNERS: Penn QST 36 balls are engineered for beginner players ages 8 and under, helping kids develop proper swing mechanics, timing, and confidence on the 36' courts. 75% SLOWER BOUNCE FOR BETTER CONTROL: Reduced-speed design allows longer rallies and easier ball tracking, making learning tennis more fun and less frustrating for young players. USTA APPROVED: A high quality and consistent ball, Penn QST is approved by the USTA for the 10 and Under Tennis Program. DURABLE PENN QUALITY CONSTRUCTION: Made with consistent bounce and durable felt, these balls are built to withstand repeated practice on 36' courts and beginner drills.