The OXYGN A3™ is the BUTTONLESS Flip-Up visor helmet. We have taken our extremely popular OXYGN™ helmet and brought it to the next level. "Vision and air!" Our newest technology revolutionizes the conventional flip-up lens, providing superior performance and peripheral vision. The helmet's lower profile sides and easy to use lens eliminate the need for a safety snap or tuck feature. The OXYGN A3™ has an exterior audible altimeter port that will accept ALL major brands of Audible Altimeters including Pro-Dytter, Time-Out! and Skytronic Pro.