It is the staple of business around the world, the classic white dress shirt. It usually needs to be laundered or cleaned and ironed. Don Draper kept half a dozen in his desk so that he could change them through the day and always look fresh.
pull heat away from your body and actually store it in the shirt - like a battery. This way, when you get back into your AC'ed office, the shirt will release the heat back to you and keep your skin at the temperature it should be at. The difference is noticeable, and can change your day.
Indeed, that is how PCMs are used in buildings, to act like thermal mass and hold heat from the day to release at night, and vice versa. It should help keep you cooler with less air conditioning.
The shirt also has odor control, moisture management, and "dynamic motion". It's no-iron, formaldehyde free and made in the USA.
What the designers of this amazing bit of technology do not explain is why people wear such dumb things as white dress shirts in the first place, so impractical and high maintenance that fixing it is as complicated as the Apollo project. More at their Kickstarter site