SOLES All Alpina XC boot soles are NNN compatible. Sole type and construction are chosen individually for each boot based on boot features and functional requirements. NNN XCELERATOR Top racing sole with neutral foot position provides more direct power transmission; light, with optimised flex and torsional stiffness; different hardnesses for skate and classic shoes; PEBAX-made. HEEL COUNTERS FULL CARBON ACTIVE EDGE Extremely light. Improves the torsional stability of the boot and provides excellent grip and foothold in the heel. With its Active Edge construction adopts to various types of heel and heel shapes. ANATOMIC FOOTBED Insole contributes significantly to the vertical stability of the foot, providing a high level of comfort and improves the thermal insulation of the shoe. GAITERS One-piece seamless gaiters cover the shoe and lower leg completely. Gaiters are water-tight, with a water-tight zipper and elastic, and protect against cold, water, moisture and snow. And the boot instep is adaptable to different foot shapes. PVC NEOPRENE PVC is strong and lightweight, soft and flexible, and highly durable, while neoprene maintains good flexibility over a wide temperature range and offers good insulation against both wet and cold.