Catcher's mitts are called "mitts" because they lack individual fingers, like mittens. They have extra padding and a hinged, claw-like shape that helps them to catch 90+-mile-per-hour fastballs, and provide a good target for pitchers to throw at. If required to catch a knuckleball, a catcher will typically use an even larger mitt. Sizes of catcher's mitts, unlike those of other gloves, are measured around the circumference, and they typically have 32- to 34-inch patterns.
First baseman's mitts also lack individual fingers. They are generally very long and wide to help them scoop badly thrown balls from infielders. These mitts usually have 12.5- to 13-inch patterns, measured from wrist to the tip. Note that, because first basemen are often left-handed, first baseman's mitts are readily available in right-handed versions.
Infielder's gloves, other than the first baseman's, tend to be smaller. They also have shallow pockets to allow the fielders to easily remove the ball from their glove to make a quick throw to a base. Infielder's gloves typically have 11- to 12-inch patterns, measured from wrist to the tip.
Pitcher's gloves usually have a closed, opaque webbing to allow them to conceal their grip on the ball-which determines the behavior of the pitch-from the batter.
Outfielder's gloves are usually quite long with deep pockets, to help with both catching fly balls on the run or in a dive and to keep outfielders from having to bend down as far to field a ground ball. These gloves typically have 12- to 13-inch patterns, measured from wrist to the tip. They are frequently worn in differently than those of infielders, with a flater squeeze rather than the infielder's rounded style.
