S&R Energy Saver’s Pet film display night covers is made out of Polyethylene Therepthalat S&R Energy Savers Night covers are clear and have small perforated holes to decrease moisture buildup Night Covers are used on open refrigerated Display cases to hold the cold air and keep the inner temperature. Open Refrigerators benefit from Night covers by keeping its circulation and saving energy. If night covers are used daily based on a 6 hour closed store it can save between 35- 40% energy. Night covers are extremely easy to install and use, and have 100% Customer satisfaction. The way night cover works is after you’ve installed the night cover ontop of the cooler and its hook on the bottom. You can now scroll down the night cover and place it on the hook this will save you energy while your coolers are not in use or your store is closed. To open the night covers when you return just take it off the hook and it will automatically scroll up. (do not let go of the night cover when opening where night cover will fly up).