As with all our other Climbing Gear, Helmets come in a range of styles and sizes - just make sure you wear one !?
When choosing a helmet the style or design may dictate whether or not it is appropriate for the individual and its intended use. The following three generalisations may help you decide:
Full shell / Cradle - the traditional design for climbing helmets these feature a fully hard polycarbonate shell (plastic?) with a cradle or harness suspended inside. Examples include the very basic and economical Rockstar, the indestructable Edelrid Ultralight and the Petzl Ecrin Rock - argueably the benchmark for fit (these have two modes of adjustment and the soft tapes inside mold to the climbers head). These styles are the 'go to' for durability and great for winter climbing, caving or group use.
Full Foam Construction - these feel more like cycle helmets than climbing helmets and this is especially true of the Petzl Meteor III+ which meets the European standards for Cycling and Whitewater sports. These are the lightest helmets around and probably the nicest to wear although this comes at a cost to the overall durability. Although climbing helmets are primarily engineered to protect from rockfall and are generally stronger on the top and front, this design may offer more consistent protection elsewhere which could help when impacting during a fall. De-rigueur for super light alpine ascents, head-pointing and adventure racing.
Foam / Shell Hybrids - a partially hard shell with an expanded foam liner these are an amalgamation of the above. These are generally the most versatile and hit the right compromise between durability and weight. An all rounder, this design fits the bill for regular cragging and sport climbing everywhere. See the Petzl Elios, Black Diamond Half dome and womens specific models like the Petzl Elia.