Convert-A-Fit Sheets™ fit all types of mattresses including RV's, Sofa Beds, Pillowtops up to 12" thick, soft-sided waterbeds, airbeds, space-age Memory-Cell® and even traditional wood frame waterbeds! These sheets are attached at the center foot, so you don't have to struggle to make the bed, yet the simple stitching line allows for total sleeping comfort & a full range of movement!