Pro Penn Marathon Regular DutyPro Penn Marathon Regular Duty Tennis Balls Soft Court. Penn's longest lasting and most technologically advanced tennis ball, featuring exclusive Encore Technology and LongPlay Felt. It is the #1 choice of teaching pros and has been the official ball of the USPTA for over 35 years. Encore Technology has a unique core compound of natural and man made polymers to produce a core that limits ball softening. The result is a ball that stays fresher longer
Shopping security
Each payment you make on thelockerguy is secured with strict SSL encryption and PCI DSS data protection protocols