Very disappointed my machine is set at 10 and the mask cannot cope with it, the air escapes irrespective of how tight the head gear is. Over 3 nights I have not been able to get anymore than 2 - 3 hours sleep a night. It is exceedingly noisy and disturbs my wife's sleep as well. I would appreciate a full refund and I will send the product back as it is useless to me. I have used masks for 15 years and have not had any of the above problems. Nothing in your literature mentions about pressures minimum or maximum which is relevant to the use of the mask . I await your reply