Bern 2016 Nina Summer Satin Purple Jungle w/Flip Visor - S/M Head Size: 51.5-54.5 Zipmold liquid foam technology offers a thinner profile than the standard EPS grey foam other brands use, giving you a much smaller helmet shape. Velcro adjustable liner on back of helmet quickly secures or loosens the fit around your head, super easy to adjust - even on the fly. Cold weather liners available but not included