MADHOLLY Spa Hot Tub Cover for Heat Retention - 7×7FT Square 16-Mil Heavy-Duty Bubble Solar Blanket for Preventing Water Evaporation, Easy to Cut and Clean (210 × 210 CM)Brand: MADHOLLY Color: blue Features: Bubble side Down: When using, you need to put the bubble side of the solar blanket for hot tubs close to the water surface, with the smooth side facing up, which can also play a role in preventing dust, reducing condensation and freezing on the edge. (Tips: The cover may have creases from folding. Lay it flat and place heavy objects on top for a few hours to help it flatten out). 16 MIL Thickness: Different from