I found the sales person very helpfull but alas the mask seals are of a lint design and although they help with the leak they didn't cure it and the lint kept going into my eyes which also dried them out. It would be nice if you had trial masks so I could try before I buy as a mask that doesn't seal properly is a very expensive ornament. I am sure more people would buy masks if they could try first, I would willingly pay for my mask and try a loan mask for a few days if it worked great if not I could return the loan mask and get a refund. Postage costs obviously payed by myself