Pottery Barn describes as: Lustrous, smooth and cool to the touch, our sheet set is woven from fine Belgian flax. It’s enzyme washed for added softness, and its classic style complements a variety of patterns and styles. Made of 100% Belgian flax linen. Machine wash. Fitted sheet fits mattresses up to 16" deep. Set includes flat sheet, fitted sheet and 2 pillowcases. Linen woven from Belgian flax, constructed in China.