Our take Standard foam helmet design includes a plastic shell over polystyrene foam, which cracks to absorb force. Some newer foam helmets are removing the plastic shell and using expanded polypropylene foam (the same stuff found in a car’s bumper), which is designed to bounce back under force. Mammut product designers combined old and new in the Wall Rider, which has a plastic shell where climbers are most susceptible to falling rocks and head bumps—the top and front—and expanded polypropylene for the entire helmet. During six months of use, extra-large and numerous vents kept our noggins cool on hot days, and easily adjustable straps let us fit a beanie underneath on cold ones.
Crag cred “This is the lightest, most comfortable helmet I’ve ever worn,” one tester raved after a few hundred head bumps, “which makes me want to wear it even more.”