Dry suit questions

[Vtach]

Generally for recreational diving, the air comes from your first stage regulator with a separate low pressure hose.  In most cases, if you bought a new suit, it should come with an additional hose for that purpose.

The best undergarments to wear are those that wick moisture away from your body and provide a good thermal barrier.  Thinsulate is a common material used in undergarments.  I would definitely stick with a drysuit specific insulation such as Weezle, DUI, Bare, USIA, etc.  Most drysuit manufacturers also sell undergarments.  A good rule of thumb is to not go cheap on your undergarments.  The suit may keep you dry but unless you have adequate undergarments for the temps you are diving in, you won't be comfortable for long.

If trying to keep expenses down, you may be successful with some "outdoor activity" undergarments.  Something like what Cabelas or Gander Mountain may sell.  Stick with the heavy weight stuff.  Those can get pricey also so you might not save a huge amount of money and ultimately may not be as warm and a drysuit oriented undergarment.

Also make sure to take a drysuit course or have an experienced drysuit diver help you out.  The learning curve will be much quicker and safer.

Looks like you also have some good advice while I was typing. ;D