They are literally neoprene
Reviewed by Slim from Wiscaaansin on Thursday, March 14, 2013
So I know it said neoprene in the description with a rubber bottom, I just did not realize that these are made for big calved dudes. For us skinnier folk, the wide neoprene upper is loose and annoying and the rubber bottom is extra wide as well. The boots look good, have good grip but for the price I would just buy some rubber boots because they will fit better, these ones are going back in the mail today.