Pretty specific but if you have a Resmed CPAP and wear a full face mask this is a really good deal.
Full set of headgear is usually $170 and the foam cushions are $20 a piece so this is basically either $100 worth of cushions as a bonus or 6 masks for $120 and a full mask setup for an extra $50.
3G/4G can't be a requirment to use the device. People would be dropping dead in forests and there would be big court cases! (I go camping regularly)
I'd go the sd card myself if it was the cheapest option. Great that the anaesthetist told you. Once treated, it will make a difference to your life and productivity.