Heat can be ruthless in Japan in the summer: humidity and high temperatures make even going to the grocery store like a trip into the jungle. The Netsu Taisaku Neck Cooler Belt is a way to help ensure your neck will survive the heat.
The Netsu Taisaku Neck Cooler Belt works by combining water (you just soak the outer part before putting it on) and gel ice packs (that you keep in your icebox when you're not using them). Before you go out into the summer heat, fill it with the ice packs, tie it around your neck, and then just let it keep your neck area cool for hours. It's low-tech but but extremely effective!
The Netsu Taisaku Neck Cooler Belt features: