The waterbed fitted sheet is similar to the flat sheet except it has an extra triangular fabrics sewn at the four corners and both flat and fitted are sewn together by the footer so bed stays made. The extra triangular fabric sewn at the four corners in the fitted waterbed sheet are turned over the corners of the water mattress and that is how you dress your sheets on your bed. In addition, the fitted sheet is always made few" larger than the water mattress so the extra fabric can cover the mattress sides when made. The Poles attachment feature is an additional feature that is used to keep the triangular fabric fully opened so fitted sheet doesn''t come off easily. If your sheets include the pole attachment feature, you can insert 12" long wooden or plastic pole that is 0.5 inch in thickness (any pole can be used as it''s NOT INCLUDED). That Pole when inserted will keep the triangular fabric fully opened under your water mattress and makes it harder for the fitted sheet to come off. •Royal Tradition•100% Cotton, Solid•300 Thread Count, Single-Ply Construction•4" hemming with piping•Fitted sheet pockets made with POLE Attachment for better hold•Fitted & Flat Sheets are attached at the footer so waterbed stays made•Attachment features made making your bed much easier•Fits mattresses up to 15" seep with elastic all around for proper fit•Care instructions: Machine washableAvailable Sizes Include:•Super Single Waterbed Sheets Three Piece includes: One Single Flat sheet 55" wide x 96" long, One Single Fitted Sheet 48" wide x 84" long & One Standard Pillowcase 20" wide x 30" long.•Queen Water bed Sheets Four Piece includes: One Queen Flat Sheet 67" wide x 96" long, One Queen Fitted Sheet 60" wide x 84" long & Two Standard Pillowcases 20" wide x 30" long each•King Size Waterbed Sheet Set Four Piece includes: One King Flat sheet 80" wide x 96" long, One King Fitted Sheet 72" wide x 84" long & Two King Pillowcases 20" wide x 40" long eachNote! The Poles are NOT Included