isoBLOX technology delivers protection and a complete range-of-motion within the STX Cell II Arm Guard. It's a combination of unique textures and materials for a high-performance look. The full-length style of this no-slip sleeve provides incredible comfort and fit. A low-profile plastic elbow cap protects the elbow from hard checks and slashes. Adjustable upper arm strap for a customized fit. The simplified design includes fewer parts so you're focused on the game and not your gear. Size M is designed for players who weigh 91-140 pounds. Size L is designed for players who weigh over 140 pounds.