Most climbers choose to wear specialized rubber climbing shoes which are often of a smaller size than their normal street shoes in order to improve sensitivity towards foot placements and use the tightness to their advantage. Climbing chalk (MgCO3) is commonly used as a drying agent to minimize sweating of the hands. Most other equipment is of a protective nature. Rock climbing is inherently dangerous, so to minimize the potential consequences resulting from a fall, climbers use protection. The most basic protective equipment is a climbing rope. Climbing pioneers would attach the rope to themselves; in the event of a fall, the rope would usually cause injury to the climber in the hope that it prevented death. With advances in technology came the development of specialized harnesses, carabiners which are used for clipping into belay and rappel anchors and connecting gear, and belay devices which are used to catch a falling climber, hold or lower a climber and for rappelling. Eventually, the placement of bolts with the use of quickdraws led to the rise of sport climbing. Traditional climbers developed the spring-loaded camming device, which increased safety over chocks, hexes, and pitons. Some climbers choose to wear a specialized climbing helmet to protect them from falling rocks or equipment or head injuries from crashing into rocks.