Biltwell Bonanza Helmet Liner / Cheekpads The removable liner in your Biltwell Bonanza open-face helmet can get grungy after heavy use. Keep your lid fresh and clean with a new liner and cheek pads. One interior comfort liner and two cheek pads are included with each kit, and installation is easy. The liners are interchangeable within these shell sizes: XS through MD LG through 2XL