A drysuit, as the name already indicates, is made to keep the diver dry even under water. The air inside the suit allows a better insulation than water and keeps the diver warmer. The main part of the dry suit is a waterproof shell made from either a membrane type material or a foamed neoprene. Some manufacturers, such as Waterproof, also produce hybrids of both. Drysuits are typically sealed at the wrist and the neck with either latex rubber or foamed neoprene.
The insulation is partly provided by the drysuit itself, depending on the shell. A neoprene suit has more insulating power than a membrane suit. But usually, for most drysuits insulation is largely provided by thermal undergarments that can be worn underneath the suit and its necessity depends largely on the water temperature.
So, depending on where you want to dive and how warm you want to be, a drysuit may just be the right choice for you. Have a look at the Scubapro Everdry 4, which is made from neoprene and very comfortable to wear, or the Waterproof D7X Cordura, which is one of the most durable drysuits on the market today! If you are looking for a drysuit that you can travel with, then perhaps the Waterproof EX2 is the suit for you. It has a flexible zip and can be taken away in a backpack!