The Muse EPS Womens Helmet from Bern Weight: 17-17.7oz Standards: ABS Hardshell with EPS Foam Sizing: XS/S: 52-55.5cm, S/M: 54-57cm, M/L: 55.5-59cm The original visor helmet serves up a unique style with comfort & protection so whether youre on your board, bike, the slopes, or in the water, the Muse, will have a model to match your needs. The EPS is a certified helmet, unlike the Muse Hard Hatcounterpart, that is not.SO why do you want that, you ask? Why does it exist? The EPS/ Thin Shell model is a certified helmet for both bike & snow. This model uses a thin ABS shell lined with EPS Foam to create a burly lightweight lid. A certified helmet is designed to crack & absorb a gnarly impact, much like you may encounter should you take a hard spill on the hill or riding your bike. Depending on the season your helmet will come with either an EPS Summer Comfort Liner or an EPS Winter Liner & you can buy the alternating seasons liner based on your needs to keep up with you through the seasons.