The plastic is for the mattress and box spring. They sell them for pillows as well. People with allergies are often allergic to dust mites and by putting the plastic around the bedding, it eliminates the problem. My guess is that it will also prevent .....ewwwwww....just the thoughts of roaches near my beds gives me the creeps. Anyway, it is just an idea. I bet you can find them online, somewhere!