4' x 150' 2mil on White MYLARWith the white mylar, you won't lose any light as it helps dissipate light to the plants for maximum efficiency. With 98% reflectivity power, the white mylar has excellent light blocking properties, where one side of the mylar sheet is white while the other is reflective. It does not leave any hotspots on the plants. Tear Resistant: The thickness of the white mylar sheet is 2mil and does tear upon application of force, making it highly dependable. 98%