Plastic, a whole mattress slides into this protective bag, 2 mil thick. Used for protecting the mattress during birth.
Full (54" X 10" X 90")
Queen (61" X 10" X 90")
Big King (76" X 15" X 90") for extra thick pillow top mattresses
Recommended use: Put a set of clean sheets on the mattress, then put the mattress into the protective bag, and then put another set of sheets that can get soiled on top of the protective bag.