Downproof 233TC protectors allow the feathers and down pillows to breathe and provide an additional layer of quiet 100% cotton protection. Zipper enclosure makes sure your pillow stays protected. Down and Feather pillows are an investment and can last a long time with proper care; adding a high quality pillow protector reduces the need to wash your pillow and increases the pillows lifespan. Do not over-wash as you will strip the layer of downproof off. Wash at 40 degrees.