B1 is a medical-based Paralympic classification for blind sport. Athletes in this classification are totally or almost totally blind. It is used by a number of blind sports including para-alpine skiing, para-Nordic skiing, blind cricket, blind golf, five-a-side football, goalball and judo. Some other sports, including adaptive rowing, athletics and swimming, have equivalents to this class. The B1 classification was first created by the IBSA in the 1970s, and has largely remained unchanged since despite an effort by the International Paralympic Committee (IPC) to move towards a more functional and evidence-based classification system. Classification is often handled on the international level by the International Blind Sports Federation (IBSA) but it sometimes handled by national sport federations. There are exceptions for sports like athletics and cycling, where classification is handled by their own governing bodies. Equipment utilized by competitors in this class may differ from sport to sport, and may include sighted guides, guide rails, beeping balls and clapsticks. There may be some modifications related to equipment and rules to specifically address needs of competitors in this class to allow them to compete in specific sports. Some sports specifically do not allow a guide, whereas cycling and skiing require one.