Hold-Up Brand Crisscross Fitted Sheet Strap Stay-downs with US Patented Gripper Clasps Usa Made Thick Ace Bandage Type Poly-blend Elastic Fabric Straps Made in USA These Fitted sheet straps attach corner to corner in seconds without lifting any size mattress U.S. Patent #8429773 with exclusive Velcro length adjustment system and the Patented Gripper Clasps hold tighter the harder you pull on them. Simple one person installation NO LIFTING and works on hospital motorized bed and any size and thickness of mattreses US Patented Composite Plastic GRIPPER CLASP will holdup to years of use and are washable Works on any size fitted Mattress sheet from twin to Calif. King to eliminate crumpled looking sheets due to worn out fitted sheet elastic corners.