The stumps are three vertical posts which support two bails. The stumps and bails are usually made of wood, and together form a wicket at each end of the pitch. The overall width of each wicket is 9 inches (22.9 cm).
Each stump is 28 inches (71.1 cm) tall with maximum and minimum diameters of 1 inches (3.81 cm) and 1 inches (3.49 cm). They have a spike at one end for inserting into the ground, and the other end has a U-shaped 'through groove' to provide a resting place for the bails.
Each stump is referred to by a specific name:
In modern professional play, the stumps are often emblazoned with a sponsor's logo. Although they are too far away from spectators to be seen, such logos are visible on television coverage.
For professional matches, often one or more of the stumps is hollow and contains a small television camera. This is aligned vertically, but can view through a small window on the side of the stump via a mirror. The so-called stump-cam gives a unique view of play for action replays, particularly when a batsman is bowled. Stump Cameras were first used in the 1992 Cricket World Cup in Australia and after the success of them they have been used ever since.
Being "out of his ground" is defined not as having any part of the batsman's body or his bat touching the ground behind the crease - ie, if his bat is slightly elevated from the floor despite being behind the crease then he would be considered out (if stumped). One of the fielding team must appeal for the wicket by asking the umpire. The appeal is normally directed to the square-leg umpire, who would be in the best position to adjudicate on the appeal.
Stumping is the fifth most common form of dismissal after caught, bowled, leg before wicket and run out. It is governed by Law 39 of the Laws of cricket. It is usually seen when a medium or slow bowler is bowling. It requires co-operation between a bowler and wicket-keeper: the bowler must induce the batsman to move out of his ground, and the wicket-keeper must be quick enough to break the wicket before the batsman makes his ground (i.e. places the bat or part of his body on the ground back behind the popping crease). If the bails are removed before the wicket-keeper has the ball, the batsman can still be stumped if the wicket-keeper removes one of the stumps from the ground, while holding the ball in his hand. The wicket-keeper and the bowler both obtain credit for dismissing a batsman who is stumped. A batsman may not be out stumped off a no ball, but may be stumped off a wide delivery.