Arai Xd-5 Intpad Helmet Liner Replacement top liner for the Arai Xd-5 family of world-class ADV helmets. Compatibility: Intpad helmet liners come in 5 unique sizes Only helmet sizes MD and LG share an Intpad liner size (Size Iii) The factory liner thickness for each helmet size is stated Intpad liner thickness can be ordered thicker and / or thinner than factory pad thickness for a more tailored fit See Arai Interior Lining Thickness chart for graphical representation of sizing and compatibility Specifications: Size XS Helmet: Requires liner Size I Factory thickness is 7mm 10mm optional thickness Size SM Helmet: Requires liner Size II Factory thickness is 7mm 5mm and 10mm optional thicknesses Size MD Helmet: Requires liner Size III Factory thickness is 10mm 12mm, 7mm and 5mm optional thicknesses Size LG Helmet: Requires liner Size III Factory thickness is 7mm 12mm, 10mm and 5mm optional thicknesses Size XL Helmet: Requires liner Size IV Factory thickness is 7mm 5mm and 10mm optional thicknesses Size 2XL Helmet: Requires liner Size V Factory thickness is 7mm 10mm optional thickness Note : Only helmet sizes MD and LG share an Intpad liner size (Size Iii).