To have a maximum safety the helmet must fit tightly and be correctly and securely fastened, in order not to be able to be taken off neither by pulling it nor by rotating it around the head. If it is too big, it may slide down over the eyes or turn in a lateral direction due to movement during riding, blocking the right visibility. Safety Shell in reinforced thermoplastic resin, moulded by injection. Internal polystyrene in two sizes (M and L). Internal Polystyrene protective lining, available in two sizes (M and L). The special shape and construction in different density increases mechanical resistance in the event of accidental shock. Inner channels studied in the wind tunnel guarantee a perfect ventilation. The D-Rind Retention System has been designed and patented by Suomy. Insert the free side of the strap in the rings. Pull the end until the strap presses firmly against the jaw. After this operation, it should not be possible to remove the helmet. Verify that by grabbing it from the back and rotating it to the front it cannot be removed and it is fixed to the head. If the helmet tends to come off or rotates freely, tighten the strap again until the right pressure is obtained and repeat test. If after repeating the test you are not able to efficiently tighten the retention system, do not use the helmet. Only after checking the correct tension of the strap, fix the free end locking it with the automatic stud to the release tab. The automatic stud is necessary only to fix the free end of the strap to prevent it from flapping while riding. Fixing the release button does not assure that the helmet is correctly in position and properly fastened: the correct locking of the strap must be verified exclusively following the above paragraphs. ECE 22-05 Comfort Cheekpads completely removable and washable with different thickness to get a perfect customization of the helmet. Internal Shell completely removable and washable, in different thicknesses for a complete customization of the product. The internal removable shell has been studied for an uniform stand on the head. The visible channels allow the air flow to check the temperature in the internal part of the helmet and to let off the hot air through the back part. Ventilation The shell is in polystyrene with channels for air flows. In the front part there are upper and back air ventilations, which help the internal helmet ventilation. On the chin guard there is an air ventilation for the front ventilation. Aerodynamics The Outer Shell has ribs to channel better the air flows. Peak adjustable and easily replaceable.Note Please note that as long as nothing else is written in the article description, all helmets that have a visor as standard will be delivered with a clear one, even if it is shown differently.