Neoprene skirt material anyone know of this?

Had a guy ask me about Neoprene skirt material I never heard of it. IF you have help me out.

I know some of the collars are neoprene but not sure of neoprene skirts - Not sure if the Bio-Flex from fishingskirts.com are or not.

Think I would go back to him and ask him if he has a example, I have had some people refer to Silicone material as neoprene.