These made-in-Japan masks create a blissfully warming, moisturizing temperature of 40 degrees Celsius (100 degrees Fahrenheit) - the same warmth as a nice hot bath. The heat relaxes your eyes and, by extension, your whole being, for a full 10 minutes or more.
Other varieties of eyemask also available: Unscented, Chamomile & Ginger Aroma, Lavender & Sage Aroma, and Menthol.
See the official Kao website:
for more product details (but note that those on sale at GoodsFromJapan have 14 masks per pack, not 5).