source: When you’re cold, the jeans start off as blue. As you warm up, the color of the jeans fades to white. The color-changing effect works with thermochromic dye that has a molecule inside that augment their hue based on temperature range.
The Canadian brand is also behind fashion items like the pair of scratch-and-sniff jeans, glow-in-the-dark jeans and a pair of jeans so thick and heavy that they could stand on their own.
He wouldn't ever pay for a pair, but if He was gifted a pair, He probably wouldn't say no. This just really really makes He miss those hyper-color t-shirts from the old days.