You can do it with a wet towel or with a bag of peas in a scarf. But when the heat goes as high as it does in Tokyo in July or August, you need something stronger, more consistent and, since this is Japan, something more high-tech. In other words, the Neck Cooler Mini, a wearable personal device whose design could have jumped out of a sci-fi novel or movie, but which guarantees that those very sensitive square inches at the back of your neck will stay cool at a balmy 10-15°C (50-59°F).
Hook it on your PC's USB port if you are at home or at work, or to the (optional) battery pack if you are out and about. Adjust the size so it will fit comfortably around your neck, fire it up (so to speak), and the Neck Cooler Mini will take care of the rest for as long as you need it (up to 20 hours with the battery pack). Light enough you will barely notice it (nor will it get in the way if you are working), it will become your essential summer accessory - made by people who really know what heatstroke means!
The Neck Cooler Mini features: