Nikken 16821 PowerSleep Magnetic Sleep Mask. Transform your night's rest or any time into an extended power nap. The Kenko PowerSleep Mask includes patented DynaFlux® Magnetic Technology that produces an area of magnetic flux extending farther and penetrating more deeply. DynaFlux is the only design that can increase the magnetic depth of field without an increase in gauss strength. The PowerSleep Mask has a comfortable, washable surface and is provided with its own carrying pouch.