【What is SpeedFlex?】 The SpeedFlex is a helmet designed for maximum performance and protection. It absorbs impacts from the side, which can cause concussions. The inner padding uses a variety of materials to achieve optimal impact absorption. It is also molded to fit the curvature of the head for a natural fit. 【Reason for Listing】 I imported this from Riddell.com in the US, but the size didn't fit, so I am listing it. 【Measurement Method】 Wrap a cloth measuring tape around your head. Measure with the tape about 1 inch above the player's eyebrows. Use the Riddell circumference chart above to select the appropriate helmet size. If your measurement falls between helmet sizes, select the smaller size. ■SPEEDFLEX S - 51.7 cm M 51.7 - 55.8 cm L 55.8 - 59.6 cm XL 59.6 - Thank you for viewing. The SpeedFlex model itself is a rare helmet that is not often listed on auctions. Since it is new and unused, the price is a bit high, but it costs about 150,000 yen to buy at a QB club, so it's a bit of a bargain. Price reductions are negotiable.