UltraCool-IR8035T 35% VLT Transitional IR Solar Film isa transitional polyester film that darkens when in direct sunlight. This premium grade, sputter-coated, transitional polyester film reacts to ultraviolet light which is what makes it far superior to all other IR window films. On sunny days, the film reacts to the sunlight intensity and becomes darker to reduce sun, heat, and glare. On cloudy, rainy days and at night it remains lighter, maximising available daylight. Manufactured under 1000-level cleanroom conditions to maintain optical clarity, the darkening and recovery process was repeated over 5000 times without any loss in photochromic activity. This film is an excellent choice for high visibility, fade protection, heat reduction, and for automotive applications.