Often they are worn under an oversuit, since they are more flexible and less durable. Unlike diver suits, surfer suits are mass-market items which makes them cheap and widely available new and used. Nylon on the outside gives a bit more abrasion resistance, but also increases stiffness. It looks comfortable, and may allow sweating when out of the water. I don't know anyone who has tried it for caving.
Neoprene is of two main types.
See the Appendix for more information. Some cavers wear coveralls, rubber jackets, or shorts over their wetsuits. The thin surfer suits are well-suited to wearing under coveralls, both to protect the suit and provide more warmth. Plain wetsuits look good in photos, since they accentuate the human form more than baggy clothing. Accessories Extra zippers , such as ankle or wrist zippers, should be avoided.