Our Pillow Protectors are T180 Thread Count made of 50% polyester and 50% Cotton. Our Envelope / Flap Pillow Protectors have easy design to slide pillow inside the pillow protector. The optimum polyester / Cotton blend makes our Regal Brand Pillow Protector Stronger, Long Lasting with Shrinkage Control. Our Protectors are Wrinkle Free with No Ironing Required. Use of Premium Processes in Weaving, Bleaching, and Stitching makes the Northern Mills Bed Linen the Best Bed Linen in the Industry.