The ccm resistance r100 helmet is designed to maximize protective capabilities while maintaining a comfortable fit with the multi density vn foam liner easy adjustment at the back of the helmet that will allow a fit to a high level of comfortmulti density vn foam linersingle tool free adjustment that adjusts both length and width in one movementcage fitting fm580helmet sizessmall 51cm 56cmmedium 55cm 59cmlarge 57cm 62cm