In the sport of cricket, batmen often wear a helmet to protect themselves from injury or concussion by the cricket ball, which is very hard and can be bowled to them at speeds over 90 miles per hour (140 km/h). Cricket helmets cover the whole of the head, and have a grill or perspex visor to protect the face. Often constructed with a carbon fiber and Kevlar shell, the helmet is designed to deflect cricket balls as well as shield the wearer from impact, and its liner includes an inflatable element to tightly fit the helmet to its wearer's head.