Has Many Uses-Suitable for futon mattresses, air mattresses, foam mattresses, tablecloths, barbecue covers, car/boat/motorcycle/scooter seat covers, chair covers, etc. Flat-Keep the sheets in a stretched state every day, no need to readjust every night, the sheets won't wrinkle anymore; Durable And Practical-The elastic band in nylon has strong metal clips to help hold the corners in place, and the plastic splint in the middle of the clip protects the fabric from damage and prevents slipping. Extra Long Size-Allows you to stretch as you need, adjustable from 61cm to 220cm, to fit sheets of different sizes. Easy To Install- Just open the metal clip and place the two sides where you want it (at the corner of the sheet) to ensure a firm fit.