Andux Land Elastic Bed Sheet Fasteners Suspenders, Black, Set of 4 CDJ-02 4 straps, one used diagonally for each corner of the bed. Great For Bed Sheets and Mattress Covers. Metal Clasps For Secure Grip. Lift mattress and fasten one clip to edge of sheet . Repeat above for all 4 corners. Keep bottom sheets and mattress covers in place, also suitable for hide-a-beds, adjustable beds, inclining beds, baby's cribs and more.