Do you have a child who complains of wrist pain from practising all those cartwheels, back handsprings or handstands?
Try these fabulouse Jelleez eggs.
Sold as a pack of 3 - yellow is the softest and blue is the firmest, so they slowly build their hand and wrist strength up over time.
And believe me, they are really really nice to squueze. Much better than any squishy and actually useful.