The key to staying warm in your drysuit. This is one of the most important but often overlooked items for staying comfortable on those long dives. Make sure to match the correct undergarment with the diving conditions.
By FAR our absolute favorite undergarments is the line by Fourth Element. They are sure to have the correct layering for the water temperatures you are diving. It is the undergarment we dive exclusively and have dove it from the tropics to the arctic!