It's a sponge with a scrubbing pad on one side and a polishing pad on the other. It is marketed for cleaning glass ceramic cook tops but I had a stainless steel pot with a stain in the bottom that I couldn't get out so I tried the Scrunge and it worked great. I just tried this a couple of days ago and haven't tried it on the boat yet. The Vileda web site I found is Canadian but there must be products like this in the US. There are other Scrunges for other surfaces, the one I tried is the glass ceramic Scrunge. No chemicals, just water.

http://www.vileda.ca/en/scourers/ceran/