This 4-piece sheet set perfectly fits a 42-inch truck mattress commonly found among OEM cab mattresses. May also fit certain RV mattresses but always measure first. The attractive blue color of these truck linens is less likely to fade because they are made of 100 percent polyester. Fade-resistant and wrinkle-resistant. The fitted sheet for the cab mattress comes with a handy pocket to store your reading glasses and cellphone or any other truck accessories you need to have close at hand while you sleep or nap inside your rig.