For more than twenty years, elastic-strap fielder's masks have slipped and shifted, compromising protection and play. NEO(TM) reimagines the softball fielder's mask; extensively designed and tested specifically for softball and delivering a pioneering, patent-pending, dial-fit retention fitting system along with added protection and sleek lines. NEO sets new safety and performance standards for softball players of all ages and levels. FEATURES: Locked-In Fit: NEO is the first fielder's mask with a patent-pending dial-fit retention system Better Protection: ExoShield outer shell made with ABS plastic - the same material used in batting helmets. Tested to stay secure on impact at 70+ mph Hairstyle & Freedom: Open back design comfortably accommodates ponytails, braids, etc. Easy on, off, and adjustability gives athletes complete control of their Neo ADDITIONAL DETAILS: Size Guide: M/L - 22-1/4 inches head circumference and above (or if currently wearing an adult mask) How to Measure: Use a soft measuring tape and wrap it around your head, keeping the tape level and positioned just above your eyebrows and across your temples. Make sure it sits snug - not too tight - and note the measurement where the tape meets. For the most accurate fit, measure twice and use the larger number if you're between sizes