I used to use US Open balls, we play with them and then put them in our practice basket, we noticed we couldn't keep them in the basket as long because they were becoming dead sooner. we even opened quite a few cans over the the last couple of years that were still sealed put upon opening the can noticed after the first hit that they were dead! These Penn balls last longer, and after a year of using them have never opened a bad can. We travel to tournaments a lot and noticed an amazing number of clubs are using them that used to use the Wilson balls.
These balls last forever. I'm a 4.0 player who plays with a 5.0 player. We hit the ball pretty hard and they last set after set. More expensive but well worth the price. I have opened up two other cans of balls (Wilson US Open & Dunlop) for comparison. There truly is NO comparison. These balls last set after set.
Opened the can on Monday, played for two hours, and played with them again the following Monday. Excellent balls! Tom
These are the best, most durable tennis balls I have ever played with. They play the same in the 5th set as they did in the first and are even good to hit with days and days after they were opened. Very HOT balls!