Letus Black Roman Blind is the best thermal roman blind for insulation. It is perfect to keep heat in and cold out. The material is 100% polyester with blackout rate 100%. It has three layers: 1. The polyester layer which makes it durable, easy to clean, resists wrinkling, shrinking, and stretching. 2. Blackout layer: Block out light 100% keeping your room pitch black. Perfect for bedroom and TV/entertainment room. No extra costs for blackout linings. 3. Thermal layer: prevent heat from escaping through the window, keep your room warm as well as reduce electricity costs.