These made-in-Japan eyemasks 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, Yuzu Aroma, Chamomile & Ginger, and Menthol.
For more details, see the official Kao website:
http://web.kao.com/sg/megrhythm/index.html
(but note that those on sale at GoodsFromJapan have 14 masks per pack, not 5).