Softball cleats provide ankle support and traction on dirt and grass. There are strict guidelines on softball cleats in order to reduce the risk of injury. First, the studs themselves can not be made out of metal or even some types of hard plastic (although metal cleats are permitted in high school softball except in Maryland, New Jersey and Massachusetts). Second, the studs cannot extend more than 3/4 of an inch from the shoe. Removable spikes are also not allowed. As with other shoes, comfort and fit are crucial for performance. Most softball cleats can be purchased using street shoe sizing as a reference.