Appropriate maintenance involves reconditioning of the helmet at the very least each two (2) years by NOCSAE Certified Reconditioner using only new factory replacement liners while in the reconditioning system. Evidence of any of the following conditions will operate to void this guarantee: Request a Quote View the Video clip https://brooksogffd.suomiblog.com/the-smart-trick-of-riddell-speedflex-adult-large-that-nobody-is-discussing-46424891