Hard Shell Helmets: Construction:  These helmets have a hard shell consisting of ABS plastic and an inner EPS and/or EPP foam to absorb impact. The hard ABS plastic protects the inner foam from penetrating objects and aids in dispersing forces while the inner foam absorbs the impact. Intended Use:  Applications where durability or pricepoint are valued over size and weight.  Ideal for climbers on a budget or high-use applications (e.g. school groups, rentals, etc.).    In Mold Helmets: Construction:  These helmets are made of a combination of EPS foam inner for shock absorption and a thin outer layer of polycarbonate or composite material for durability and to protect your head from top-down impacts. In Mold helmets are lighter and have a lower profile (more stylish) fit than Hard Shell helmets. These Helmets are also the most delicate helmets since Polycarbonate is more flexible than ABS and provides less structural protection for the EPS foam inner which can crack if bent.  Intended Use:  Every style of climbing from the Crag to the Alpine.  Ideal for climbers who are willing to pay a little more for lightweight low profile performance and are prepared to treat their helmets with care. Hybrid Helmets: Construction: Hybrid Helmets are the lightest, most breathable and highest-performing helmets on the market. The difference between these and In Mold helmets is Hybrid helmets don't have hard outer shell materials around the bottom 2/3rds of the helmet. Instead, an EPP foam shell is found to absorb impacts and provide protection. Since EPP bounces back after deformation, EPP foam can withstand some compression and therefore Hybrid Helmets don't need to be treated with the same extreme care as In Mold Helmets. Also, since EPP can withstand multiple impacts, these helmets are a more durable choice for climbers heading to remote destinations where it isn't possible to replace your helmet mid-trip. Intended Use:  Every style of climbing from Crag to Alpine.  Ideal for climbers willing to use lightweight and smaller (more fiddly) buckle/adjustment systems and who value the highest ratio of weight-to-protection combined with enhanced durability.