This is the stock pad that goes on the top inside of your S1 Lifer helmet. A perfect medium between our larger 8mm and smaller 2mm top pad. It is compatible with both Mini Lifer, Lifer and Mega Lifer helmets. It will stick to the top of your helmet with velcro. This size top pad comes in every S1 Lifer helmet standard and is the stock/recomended replacement.