Both wooden and metal alloy (generally aluminum) bats are generally permitted in amateur baseball. Metal alloy bats are generally regarded as being capable of hitting a ball faster and farther with the same power. However, increasing numbers of "wooden bat leagues" have emerged in recent years, reflecting a trend back to wood over safety concerns and, in the case of collegiate summer baseball wood-bat leagues, to better prepare players for the professional leagues that require wood bats. Metal alloy bats can send a ball towards an unprotected pitcher's head up to 60 ft 6 in (18.44 m) away at a velocity far too high for the pitcher to get out of the way in time. Some amateur baseball organizations enforce bat manufacturing and testing standards which attempt to limit maximum ball speed for wood and non-wood bats.
Within league standards there is ample latitude for individual variation, many batters settling on their own bat profile, or one used by a successful batter. Formerly, bats were hand-turned from a template with precise calibration points; today they are machine-turned to a fixed metal template. Historically significant templates may be kept in a bat manufacturers' vault; for example, Babe Ruth's template, which became popular among major-league players, is R43 in the Louisville Slugger archives.