Bests & Worsts Reviews from Amazon

these things really do filter 99% of light. You can tell its day outside, but you will not be disturbed by light. The curtains are held on the rod with loops, kinda like belt loops. so you can easily get the two sides to over lap each other so as to not worry about light getting through the middle. and the curtains aren't scruffed like the look in the picture, you can draw them out most of their length. So if you have about a 48" or less window, you'd only need one curtain to cover the entire thing. They do mask sound somewhat, but not enough to really list as a feature. However the heat these things refract is amazing.