You wear a helmet every time you ride. It only makes sense that you would protect Alpinestars MTB Bionic Jacket protects your chest, back, shoulders, and elbows, and it does it all while letting cooling air flow through the jacket so you don't overheat. The jacket's main body is made with lightweight open mesh and Lycra. This combination forces fresh air through the jacket to cool you off and provides an unlimited range of motion. The chest and back protectors are made with Thermoplastic rubber and backed with an 8mm foam panel to soften impacts. The back panel is actually five separate plates that work together to move with your back and prevent over extension. Both the chest and back protectors are compatible with Alpinestars' Bionic Neck Support. The shoulder and elbow protectors are made with polyurethane shells and backed with lightweight, low profile foam pads. When you don't need them, the sleeves zip off to leave the shoulder pads intact and your arms completely free but unprotected. An integrated kidney belt eliminates bunching around the waist with thin strips of stretch material.