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 Brand•Solid 100% Cotton from long stable yarn•450 Thread Count per square inch •Flats and pillowcases made with 4" hemming •Fitted Sheet Pockets Made With POLE Attachment for Better Hold•Poles are Not Included•Deep fitted sheet fits mattresses up to 15" deep and fully elasticized for snug fit•Machine washableAvailable Sizes Include:•Super Single Set Includes: 1-Flat sheet 55x96", 1-Fitted 48x84"�, and 1-Standard Pillowcases 20x32" each. •Queen Size Set Includes: 1- Queen Flat Sheet 67x96", 1-Fitted Sheet 60x84", and 2- Standard Pillowcases 20x32" (51x81cm)each•King/California-King Sets Includes: 1-Flat sheet 80x96", 1-Fitted Sheet 72x84", and 2-Pillowcases 20x40" each.