The new ventilation system makes this a quiet CPAP mask and the air diffuses away from you and your partner for minimum hassle. Patented technology keeps the mask on securely while the headgear flexible design allows you to spread pressure evenly around your head without compromising on performance. Breath-O-Prene Headgear offers premium therapy and top of the line comfort for BiPAP and CPAP therapy. This new model has replaced the over-the-head straps with a four strap system above and below each ear. The ventilating holes are on the elbow, and Fisher Paykel has included a filter to reduce noise. The HC405's headgear attaches securely so that you can move around without disrupting the mask's fit.