This article was taken from

http://www.usssa.com/usssa/usssa-general/2005ModifiedPlayingRules.htm

RULE 1 - DEFINITIONS

Sec. 1     ALTERED BAT: A bat is considered altered when the physical structure of the legal bat has been changed.  Examples of altering a bat are replacing the handle of a metal bat with a wooden or other type handle or inserting material inside the bat.  A flare or cone grip is considered an altered bat.

Sec. 2     APPEAL PLAY: A play in which an umpire cannot make a decision until requested by a manager, coach  or player.  The appeal must be made before the next legal or illegal pitch or before all infielders (including the pitcher) have left the field ( crossed the foul lines).

Sec. 3     BALL ROTATION: A pitcher will have a choice of balls at the start of each half inning with the  exception that if both balls do not get put into the first half of the first inning the pitcher in the bottom of the first inning must pitch the unused ball.  After every third out the ball in play must be returned to the  sixteen foot circle.  The pitcher now taking the field has a ball to start the next half inning.  Before throwing a warm-up pitch the pitcher may request to pitch the other ball, giving the ball in his possession to the plate umpire.  A choice has now been made and the pitcher must pitch his ball until it goes out of play or becomes blocked.