OLS White external shade is designed for protection against greenhouse overheating. It is made with highly reflective white films rather than aluminum foils. While other shades block light, OLS White is designed to reflect light and heat. It does not retain heat during the night but provides daytime shade to cool greenhouse temperatures. This product can be manufactured in 30, 40 or 50 percent shading. It can be installed in a suspended retractable roof, rolled over a hoop-style house or permanently attached to the roof.from Ludvig Svensson, Inc.