The Oak Pro Aluminum Elbow Guard sports a dual level of protection sandwiched together. The outer layer is a highly shock absorbing material that is derived from F1 applications and the inner features a material with excellent moldability and cushion. An elbow guard that conforms to your body will be more comfortable and the perforated material ensures adequate venting. The Pro increases protection over the standard version by adding an aluminum hard shell. Comfort is not forgotten as Dainese uses a BOA® system to give a close and comfortable fit. The Boa® system uses internal wires that are tensioned with a dial. Similar systems are used in ski boots to keep them snug and comfortable.