Though many climbing helmets may be small and lightweight in design, the best climbing helmets offer maximum comfort despite their size. This is particularly true of those that prioritize safety over comfort. EPS foam was once the standard material used for helmets, but its fragility can lead to fracture and crushing when hit against something hard, even while just moving or carrying heavy gear in your pack. Because of this issue, some models use polycarbonate shells which provide greater durability.