The lazer sport z1 fast road helmet has an integrated and non removable cover that is attached to the eps liner to create some serious advantage the z1 fats has a distinct advantage over a regular road helmet with its aerodynamic performance tests have proven that the z1 fast helmet can provide gains between 4 and 10 watt when cycling at 45 kph or a difference between 12 and 30 seconds over 40 kilometres thats the difference between ending on the podium and being the winner