"The sport models NXR and NXR2 have a wide range of use, and the adaptability of its interior parts are just as varied. Different sizes of top pad can be used to replace the original one or to adapt the upper part of the interior to one's own head shape. Center pads of a certain helmet model are interchangeable as part of their size assignment, for example ""S9"", ""S13"" or ""S17"". ""S9"" corresponds to a thinner padding and ""S17"" to a thicker padding, the thickness being expressed in millimeters. The original foam’s size is indicated on the back of the part. A tight enough but still comfortable interior will enable you to maximize your lap times on the track or make the most of the comfort of your helmet on the road. The NXR/NXR2's head pad ensures a stable fit, while its three-dimensional ribbed structure provides exceptional ventilation for an effective moisture management. The use of quick-drying materials and micro-perforated fabrics increases the level of riding comfort, whether for sporty use or long road trips. The interior of your helmet became worn out after many track sessions or a few years of road riding, or just can't be fully cleaned anymore? A replacement of the internal parts will give you back a fresh and healthy interior. Fits both NXR and NXR2 models. Attached by snap fasteners and a fastening rod. Instructions for installation and cleaning are included to the helmet manual."