Drop is the difference between the length of a baseball (or softball) bat, in inches, and the weight of a bat, in ounces. For example, a 32-inch bat that weighs 23 ounces would be referred to as a "Drop 9" or "Minus 9 drop". Since momentum equals mass times velocity, the decrease in mass is generally offset by the faster bat speed afforded by a lighter bat, and thus a batted ball will travel just as far. A quicker bat allows a hitter to swing later than normal, giving them more time to determine whether a pitch is a ball or a strike. For this reason, bats with a higher drop are generally more expensive, and leagues have established rules regarding the maximum allowable drop (e.g. most high school leagues restrict bats to Minus 3).