These 2 inch (50mm) novelty cue balls are weighted on one side and once hit they tend to take on a long curved or wobble roll. The best effect of the ball going out of control or curving is best seen when the ball is hit medium or soft and over 1/3 table distance.Makes a great partner to the 2 inch (50mm) crazy cue ball.Please Note: These are strictly a novelty item and should not be used during serious matches or competition games.