Solar heat reaches the cabin as visible light, ultraviolet and infrared energy. Infrared is the part you cannot see, and it is a significant contributor to how hot a parked car becomes. Kepler's nano-ceramic films are built to work across that spectrum with particular attention to infrared, which is why a lighter shade can still make a noticeable difference to comfort. Because the work is done by the ceramic layers rather than by a dark appearance, you are not forced to choose between a clear view out and a cooler cabin. The same films also block UV, which is what fades upholstery and trim over the years. For the numbers on a specific film and shade, check the published specifications and compare like for like.