chocks made specifically for rock climbing, with the familiar wedge shape still in use today. With Tom Frost, Chouinard invented a larger, six-sided nut called a Hexentric or hex. Prominent climbers like Henry Barber and John Stannard helped popularize the use of nuts, especially after it was discovered that a nut was lighter and easier to place and remove while climbing, as well as being at least as secure as a well-placed piton, and less damaging to the rock. Nuts are available in different shapes to help the climber find the best fit for a given crack. Curved nuts have a concave face on one side and a convex face on the other. Larger nuts can be placed in either of two aspects (hexes in three aspects) to suit different-width cracks, with either the main faces or the sides in contact with the rock. Nuts may be generically referred to as wires or stoppers, though "Stopper" is a brand name of a nut made by Black Diamond Equipment. References Nuts Mountaineering equipment