Gloves typically range in size from (youth starter size) to for adult outfield play. Catcher's mitts, unlike those of other gloves, are measured around the circumference, and they typically have patterns. The shape and size of a glove are described by its pattern. Modern gloves have become quite specialized, with position-specific patterns: 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 funnel fastballs into the pocket and provide a good target for pitchers. Some catchers use mitts with phosphorescent paint around the ridges to provide a clearer target for the pitcher. In addition, catcher's mitts come in single hinge and dual-hinge varieties. If required to catch a knuckleball, a catcher will typically use an even larger mitt. Some knuckleball catchers have even experimented using first baseman's mitts, as described below. First baseman's mitts also lack individual fingers. They are generally very long and wide to help them pick or scoop badly thrown balls from infielders. These mitts usually have patterns, measured from wrist to the tip. Because first basemen are often left-handed, first basemen's mitts are readily available to fit on the right hand. Hank Greenberg is often credited as the first to wear this style of the glove in the field. Some catchers, such as Victor Martinez, use a first base mitt while catching knuckleballers, though doing so comes with a disadvantage: because first basemen are rarely required to make a quick throw to another base, first base mitts tend to make the task of catching base stealers more difficult—a task already complicated by the knuckleball's slow speed and erratic behavior. Infielders' gloves, unlike the first baseman's mitt, tend to be smaller. They have shallow pockets to allow fielders to remove the ball easily in order to make a quick throw to a base. The webbing is often open to allow dirt to pass through the glove so that infielders do not pull out a handful of dirt when trying to remove the ball from the glove. Infielder's gloves typically have patterns. Pitchers' gloves usually have a closed, opaque webbing to allow pitchers to conceal their grip on the ball (which, in part, determines the behavior of the pitch in flight) from the batter. Pitcher-specific gloves tend to have patterns; some pitchers such as Gio González use gloves with patterns as large as .