<p>Dynarex Resp-O2 Medium-Concentration Masks are designed to effectively deliver oxygen at a concentration rate of 40% to 50%. These masks come with light green oxygen supply tubing, designed to help improve tube visibility. </p><p><strong>Features:</strong></p><ul><li>Transparent vinyl mask features smooth edges</li><li>Adjustable nose clip and elastic strap</li><li>Includes 7' of crush-resistant, star lumen oxygen supply tubing</li><li>Not made with natural rubber latex or DEHP</li></ul>