To increase batting power, I've made some used size 3 softball balls heavier by wrapping them with masking tape and vinyl tape. They are divided into white and yellow, with the colors used to practice hitting (white) and taking pitches (yellow). The vinyl tape has been freshly re-wrapped. Recommended for those who want to increase their power and practice tee-batting in a game-like situation. There are 15 yellow balls and 15 white balls.