Usually, the shell of the helmet is made of high-strength materials, such as metal, engineering plastics, Kevlar fiber, etc., through its deformation to absorb most of the impact; the lining material has the ability to absorb sweat, keep warm, and absorb shock. Military helmets often have the functi

You are standing at the base of a frozen waterfall, axes in hand, ready to ascend. You reach for your helmet, but pause. Is the helmet you used for sport climbing last summer actually safe for the shards of ice about to rain down on you? It is a common dilemma for outdoor enthusiasts transitioning between seasons.

You are packing for your first outdoor climbing trip. You have the harness, the shoes, and the chalk bag. Then you realize you don't have a helmet. You glance over at your bicycle helmet sitting on the shelf or the construction hard hat in your garage. "A helmet is a helmet, right?" you might ask yourself.

Gravity is the constant companion of every climber. Whether you are scaling a multi-pitch trade route in Yosemite or projecting a sport route at your local crag, the risk of falling rock or an awkward swing into the wall is always present. While we often obsess over the rubber on our shoes or the rating of our carabiners, the helmet is arguably the most critical piece of safety equipment in your pack.