In-mold. In-mold helmets are built using the harder exterior shell as hold for the inner lining, a special foam with high shock absorption capacity. This manufacturing process allows achieving extremely lightweight and ventilated helmets, ideal for multi-pitching. In-mold helmets are more prone to denting and are generally less durable than hard shell ones.
Hard shell. Hard shell helmets are made of two separate parts: the external hard shell and the inner lining. These types of helmets are typically heavier, but also wrap a larger head area and are more durable than in-mold helmets, making them good all round helmets.