* EXTRA DEEP POCKET SHEETS / EXTRA DEEP FITTED SHEETS: These bed sheets are for very deep pocket mattresses. They fit any mattress with pockets that are 18, 20, 21, 22 and 24 inches deep mattresses. There's a stretchable elastic around the extra deep fitted sheet which stretches for a nice tug around your mattress. Perfect for extra tall & large mattresses. Rest assured these oversized sheets will stay on tight & stay in place! * GREAT FOR DOUBLE PILLOW TOP MATTRESS: These bed sheets are perfect for mattresses with a 3 inch or 4 inch topper on top, memory foam toppers, big mattress pads, pillowtops, foam toppers, big foam toppers, pillow top mattresses and memoryfoam.