2 Faced Poly film is not only waterproof but highly reflective and is white on one side & black on the other. The white side is very reflective (over 90%) and can be used on the walls and floor of your growing area to reflect light back to your plants. The black side provides a light-proof layer. Our poly can also be purchased on easy to use rolls with an extra heavy duty 6 mil thickness. The thickest in the industry! Available in 10� x 10� individually packaged sheets or 100� boxed rolls.