Lining for Alpinestars Helmets. When selecting your crown pad, please keep in mind that the crown pad varies depending on the helmet size. In addition, the same crown pad can be used within sizes XS & S, or XL & XXL (for example, the crown pad size S – is a regular size 10. If you want a tighter fit, then you can choose the crown pad with a size 15 or 20. Please check your helmet size before purchasing your crown pad. Suitable for Supertech S-R10