Envisioned by Mark Messier! Impact technology, matrix of cylindrical cells absorb impact through lateral displacement. reduces G-forces to the brain from a hockey hit. Profit adjustment system back ratchet latch offers micro adjustment to achieve a 360 degree fit. 20 air vents to cool the player. Anatomical translucent surlyn ear covers, pro ear loops. made in the USA. HECC, CSA approved. Compatible with most face cages 7 shields/visors. Med. 22.6"-23.2", Lrg 22.8"-24.8"