What is the difference between V-KOOL k15 and x15?

[MalachiMarie]

V-KOOL k15 and x15 differ as follows: Light transmittance: Both V-KOOL x15 and V-KOOL k15 are dark films, with visible light transmittance in the range of 15~20%. The actual values are 16% for x15 and 18% for k15. The higher the value, the lighter the color, so x15 is darker than k15. Thermal insulation performance: V-KOOL x15 is the top-tier series of V-KOOL, a five-star product; V-KOOL k15 is the regular series of V-KOOL, a three-star product. In terms of thermal insulation and overall performance, x15 is one grade higher than k15, and of course, the price is also significantly higher.