Chloroban (™) is a polyester stretch fabric. 168 gsm, 50+ SPF
The secret is in the way it’s knitted. It is nearly impervious to chlorine, lasting years instead of months, and salt water does it no harm either. The acid test is the hot tub though -- and there it has no issues either. (Only the elastic in your suit will degrade in hot water).
Fast drying and very soft on the skin -- this product is ideal as a lining to board shorts too.