Hydrofarm Black & White Poly, 100' x 10', 5.5 milThe white side is over 90% reflective for use on the walls and floor of your growing area to reflect light back to plants. The black side provides a light resistant partition. Features: Waterproof and tear resistant Use as is or cut to size Available sizes 10' x 25' 5. 5 Mil sheet 10' x 10' 5. 5Mil sheet 10' x 100' 4 Mil Roll 10' x 100' 5. 5 Mil Roll