will be used to join the hex to the climbing rope by means of a loop of webbing, cord or a cable which is part of the hex.
Hexes are a type of nut, a hollow eccentric hexagonal prism with tapered ends, usually threaded with webbing, a swaged cable, or a cord. They are manufactured by several firms, with a range of sizes varying from about 10 mm thick to 100 mm wide. Climbers select a range of sizes to use on a specific climb based on the characteristics of the cracks in the rock encountered on that particular climb. Sides may be straight or curved although the functioning principles remain the same no matter which shape is selected; the lack of sharp corners on curved models may make them easier to remove from the rock.
The original Hexes were invented by Yvon Chouinard and Tom Frost, and called Hexentrics. They applied for a U. S. patent in 1974 and it was granted on April 6, 1976, and they were produced by Chouinard Equipment, Ltd until 1989, then sold as a design to Black Diamond Equipment. Hexentrics are produced and sold in much the same design today.
Hexes may be placed either as passive or active protection and are frequently carried by alpine mountaineers in place of spring loaded camming devices because of their lack of moving parts and overall lower weight for the same size crack. The hex is placed actively by orienting the webbing so that a pull causes a camming action against the rock.