Gamma Pro Tour Xtra Duty Tennis Balls (Case)

Pros: Longest lasting
Cons: A little more expensive and not discounted.

These are the best balls on the market. They play true, the color is "high optic" and best of all, they're good for three matches on hard courts. After that, they go in my ball hopper or "Slinghopper" and last forever due to the unusual pressurized filling. Worth the extra money.