For those who don't know...there isn't a better product on the market for batting training. TCBs are fantastic at providing feedback on the quality of the contact by shape and distance it takes after contact. If you have a mishit the ball will spin, flatten out, and drop to the ground...If you hit it squarely it will drive straight and stay round with very little spin. TCBs also forces you to finish your swing because it won't go anywhere if you stop at the point of contact. To really drive the ball you will need to provide backside power...arm swings will not give good results.TCBs reinforce good mechanics while helping to develop power!These balls are safe to use with composite bats. They don't fly really far so they are good for use in smaller spaces. They don't break like whiffles. They won't get blown around like foam balls. You can toss the ball or use them for tee work.This is my second round of balls...the last set lasted me 4 years of constant use by kids age 10-14 and are extremely durable. I actually have a couple left from my original set of 6, one ball had a plug the broke out after 3 years of use and the other two were lost.I have already put this set to use and expect these to last another 4 years!