Adjustable elastic design - the length of the fitted single shoulder strap can be adjusted, the shorter one can be adjusted to suit your needs. 9cm, the longest one can be stretched to 25 cm, suitable for the different needs of the family. The unlimited-unlimited sheet tensioner suitable for single or double sheets, mattress covers, sofa covers, board covers; ironing, ironing boards; ironing, tablecloths, car seat covers, chair covers, etc. The sheet stretcher is suitable for single or double sheets, mattress covers, sofa covers, skateboard covers. ironing, ironing boards; ironing, tablecloths, car seat covers, chair covers, etc. fixed bed are made of high quality nylon and stainless steel. and feature an integrated plastic pressure system; which will not damage the fabric. Durable, tear resistant corrosion and wear. Rustproof. Sturdy fixed triangles are more stable than other shapes. The triangular grip support keeps your sheets taut every day without having to. readjust them every night 1. Adjust the strap according to the size of the stationary target 2. Open the metal clamp. 3. Insert the paper and close the clip. 4. Repeat the above action so that the three clips bite into the bed sheet. 5. Adjust the buckle as needed.