Pro Penn Marathon Extra Duty String for advanced playing techniques with

for advanced playing techniques with very good spin and speed

perfect for fast swim-to-bike transitions

Composition based on highly technical polyamide fibers for even greater comfort

Padding: 15-Series Foam and Gel

classic design

Pro Penn Marathon Extra Duty String for advanced playing techniques withPro Penn Marathon is Penns longest lasting tennis ball featuring exclusive Encore Technology for a 22% longer lasting core and high tenacity LongPlay Felt for extended play . Pro Penn Marathon is the official ball of PTR because of its guaranteed longevity, durability and visibility. Pro Penn Marathon is available in Extra Duty Felt (for hard courts), Regular Duty Felt (for soft courts) and Extra Duty High Altitude (for higher altitudes). Penns