Seeing this a Riot Helmet for sale on Ebay reminded me of how much I really liked the fit and protection of the similar Riot Helmet I owned for several years.
Here is what I said about the Riot Helmets at the time I was using one:
The Riot helmet is no longer produced and has been quite difficult to get hold of. They came in two varieties the R1 and R2. Shell sizes are standard with the amount of inner foam being the deciding factor on size.