G'day Sir Snorzalot, welcome to Apnea Board.
There are quite a few different masks on the market, but most of them fall into three basic categories:
- Nasal pillows, which have a pair of soft "prongs" which fit directly into your nostrils
- Nasal mask, which covers the nose
- Full face mask, which cover the nose and mouth.
Some images and information here: http://www.resmed.com/au/en/consumer/pro...masks.html
In general, all masks have a standard size attachment, and the hoses are also standard. (The exception is that the heated type hoses have one end which is specific to the machine but the other end is a universal fit for all masks).
Each mask will have its own headgear, and in general these are not interchangeable.
With Resmed machines, you need to tell the machine which basic type mask you are using - I'm not sure how to do this on the A10, but I'm sure somebody will be able to tell you that. It's no biggie if you have the wrong setting, but the machine will work more effectively and deal with leaks better if you have the mask set correctly.
As for which mask is right for you - nobody knows! There are too many variables (head size, face shape, big nose / small nose, facial hair etc etc) to make a recommendation. You will need to try some out and see for yourself which suits you best. FWIW the Resmed P10 nasal pillows is very popular, but I personally can't stand it.