Save on laundry when you need to wash sheets. The sheet is on the top mattress, and when washing, you can just wash the envelope sheet, while the sheet on the bottom mattress can stay a little longer. It's good for the environment and it saves you extra laundry. An envelope layer is ideal if you have both a box spring mattress and a top mattress. With an envelope sheet from Juna, you will find that the sheet is always tight and perfect. Juna envelope sheets are made with a little bit of height, so it fits perfectly on top mattresses that are between 4-8 cm high. The envelope layer is made of fine-threaded percale in 100% cotton.