Scorpion Exo-R1 Air KwikWick Liner Kit Replacement KwikWick III cheek pads and helmet liner set for the Scorpion Exo-R1 Helmet. Replacement kits are only compatible within shell sizes: Xs-Md, LG, Xl-3Xl. Sizing: These 3D sculpted cheek pads have various thicknesses and contours to provide a snug, track-oriented fit Liner kits are interchangeable only within shell sizes: Shell 1: XS, SM, MD (Larger helmet size thinner pads) Shell 2: LG Shell 3: XL, 2Xl, 3XL (Larger helmet size thinner pads) See chart under Resources for full sizing breakdown