Wetsuits are worn for the warmth they offer as well as protection from coral, is case you get to close. They are generally made of neoprene and usually open cell neoprene. Some have coatings added as this make it easier to put them on and take them off.
A free diver could wear a 5mm thick wetsuit and it would be ideal for keeping him warm, where a scuba diver would require a 7mm suit to get the same results. Scuba diving wetsuits have zippers on them and free diving suits do not.
Open cell neoprene suits are easily damaged so remember to take your rings off girls because they can rip them open. Long finger nail will have the same effect so take care when putting it on and taking it off.
All wetsuits should be washed after use to remove salty water and always use a wetsuit hanger to hang it to dry. Never fold it because this can damage it leaving creases that will never come out.