Made from Nasty Pig Rubber, these are The Original Machine Washable Play Sheets. ™ They have taken the time to personally put together numerous focus groups to test their appeal. Elastic is stitched all the way around the edges of our Sheets so that they will hold their grip while you are busy losing yours. When you have finished abusing them, toss them in the wash. A must have for all you Hardcore Butt Pirates..