THE SISU AERO IS NOW AVAILABLE IN 3 SIZES. JUNIOR, MEDIUM AND THE NEW SIZE LARGE (FOR 6' OR TALLER)SISU NextGEN Aero is the newest, most powerful mouthguard from SISU and was designed with the athlete in mind. Made from non-compressible thermo-polymer, SISU NextGEN is engineered to withstand even more impact than the original Aero. Still astonishingly thin at 1.6 mm, the NextGEN delivers even more protection with its scientifically re-designed perforation pattern. Custom fit, remoldable boil-and-bite mouthguard features a wider bite pad, rounded edges and improved moldability to allow athletes to talk normally, breathe naturally and stay hydrated during the game. The NextGen offers maximum protection for full-contact team sports such as roller derby, lacrosse, football and rugby.