Best Waterproof Pillow Case perfect mate for outdoor sofas. The fabric is treated with DuPont Teflon nanotechnology, which can achieve level 4 waterproof. It is literally perfect covers for outdoor pillows. PENGI is a sun- and weather-resistant, colorfast, functional fabric. With over 200 colors, feel free to change your favorite color for your outdoor holiday pillow. After 2000 hours of exposure to the sun, the pillowcase will still not fade. We offer custom size service.