This is the stock pad that goes on the top inside of your S1 Lifer helmet. Offered in both 2mm Shallow Fit, and 4mm Deep Fit. It is compatible with both Mini Lifer, Lifer, Mega Lifer, Lifer Visor, Retro and Fullface 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/recommended replacement.