Of course, they didn't just use any old off the shelf magnet, instead designing custom neodymium iron-boron models that produce just the right magnetic field necessary to make that hard drive completely useless.

ENGADGET: Military-grade "Guard Dog" hard drive degausser

Because some users turn the crank-handle faster and harder than others, a nifty three-stage gearbox and a dynamo based on powerful neodymium-iron-boron magnets is used to ensure that efficiency is largely independent of the torque applied.

ECONOMIST: MONITOR

Dr Post's system uses magnets made of an alloy of neodymium (a rarish metal), iron and boron.

ECONOMIST: Maglev trains