Teams consist of nine players who use a leather-covered hard ball, a

wooden (in the professional game) or aluminum bat, and padded g

loves. Additionally, the batter, catcher, and home-plate umpire wear

special protective gear. Teams alternate turns in the field and at bat, the

home team batting last. One turn at bat for each team constitutes an

inning, and nine innings constitute a game. In the field there are a

pitcher, a catcher, four infielders, and three outfielders. The pitcher

throws overhand, employing a variety of deliveries (fastball, curve,

knuckleball, etc.), from the raised pitcher's mound to home plate, a

distance of 60.5 ft (18.4 m). An opposing batter attempts to hit the

pitches and safely reach base, while the fielders attempt to put the

batter out through various plays. A batter who misses three pitches, or

fails to swing at three judged hittable, is out on “strikes”; but if the

pitcher first throws four pitches out of the strike zone, the batter

obtains a base on balls, or “walks” to first base. A run is scored every

time a batter becomes a runner and crosses home plate after touching

each base in the prescribed order. When the fielding team puts out three

batters (or runners), the teams exchange places. If the score is tied at

the end of nine innings, play continues into extra innings until one team

has scored more runs than the other in an equal number of turns at bat.