Crampons are a framework of spikes that are attached to boots to provide traction on snow and ice. General purpose crampons designed for most mountaineering and glacier travel are not well suited for ice climbing. For ice climbing, specialized crampons that provide better support for front pointing is advised.

Crampons with 10 points were first introduced by Europeans in the early 1900s. In the 1930s, two additional forward-slanting points were added, thus creating today's 12-point crampons. Nowadays, 10 point crampons can only be purchased as used equipment. The two additional front points further reduced step-chopping and allowed the climber to "front-point" up steep snow and ice. The angles of the first two rows of points also determine the best use for a particular set of crampons. If the first row (front points) bend downward and the second row is angled towards the toe, this reduces calf strain by allowing the boot heel to be lower. In this case, these crampons are better suited for front-pointing. When straight points are used instead, the crampons are much better suited for general mountaineering.

Table of contents
1 Instep (4/6 point)
2 Hinged versus Rigid
3 Reference

Instep (4/6 point)

Scramblers and backpackers who have the need to cross an occasional low-angled snow field, can purchase smaller four or six point instep crampons. Since these style of crampons do not have points on the heel or toe, they do not work well for mountaineering, steep snow slopes or ice.

Hinged versus Rigid

There are also two types of crampons: hinged and rigid. Hinged crampons provide flex at the instep and bend with the natural motion of walking and thus are the preferred style for almost any type of mountaineering except steep technical ice climbing. A rigid crampon does not bend at the instep so when climbing up steep technical ice, they allow the climber to keep their heel lower when front-pointing, thus less tiring as a result. However, rigid crampons tend to be heavier and will not perform as well in mixed terrain. Generally, most people will buy hinged crampons.

Reference

Mountaineering: The Freedom of the Hills, 5th ed.