Quality elastic corner straps to fasten around the mattress Corner elastic straps, to prevent the sheets from getting out of place, and to hold the sheets tight and snug all night long ***Merino Wool Underblankets are "Woolmark" certified. The Woolmark Company promotes wool in the world by initiating research and development works. Quality standards for the products made of 100% wool and combinations with wool. Our core business is natural bedding that enable our customers to achieve a better night sleep. ***Reversible Padded- cotton base with Merino wool fleece We recommend sleeping on the underblanket wool side up.It may be turned and used the cotton side up in the summer time.Sleeping in dry conditions offers relief from aches and pains such as Arthritis, Rheumatism and back ache. *** Healthy body-friendly product Wool is not only a raw material. It is recommended as a healthy body-friendly product In the today's world dominated by synthetic fibres the prophylactic and therapeutic properties of wool are discovered again. Do not spin-dry.