Caving clothing consists of a two layer system - an undersuit and an oversuit. The Undersuit is a warm layer, generally made of some sort of fleece. The oversuit protects the undersuit from water, mud etc. and keeps the worst of the breeze out. These two layers work together to keep you warm and relatively dry in the cave.
Oversuits are generally made from either PVC or Cordura. Cordura oversuits are hardwearing and offer a good amount of friction with the cave walls on those tricky downward slithers. They have the advantage that a small rip will not generally turn into a large tear quickly and so those more inclined to caving than to sewing don't need to repair them straight away. A cordura oversuit will not be as water resistant as PVC, but won't have the same "boil in the bag" effect in a dry cave.
PVC oversuits are ideal for wet caves as the material is fully waterproof (although obviously water will still get in through the neck - sleeves). We are currently trying to source a range of PVC oversuits, but if there's anything you want in particular let us know!