Just a note— make sure you don’t give Tretorns to the dog. They are filled with white powder which can make quite a mess and is probably not good for the dog when she chews through it. Trinitis and pressurized balls are ok.Tretorn makes pressure-less balls--hard as rocks but should last forever. With the "supply chain problems" Tretorns may be the ball of the future--no more giving used balls to the dogs.
I find Triniti tooooo bouncy on hardcourts.
Might work better on artificial grass I mostly play on these days.
Much prefer Babolat Academy Golds (I've no connection with Babolat).