Flannel 100-Percent Cotton 4-Piece Sheet Bed Set Flannel Sheets (King, Light Blue) 100-Percent cotton flannel. Machine wash cold, Each sheet set includes one flat sheet, one fitted sheet and 2 standard pillowcases.cycle; do not bleach; tumble dry low, iron as needed. Flannel provides luxurious softness in a breathable weave. Machine wash cold, gentle cycle; do not bleach; tumble dry low, iron as needed. The fitted sheet is fully elasticized for a secure fit.