Others just anchor themselves to a handheld device, like the Zippo Lighter app.

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The smallest one, the Reserve, is a 700 milliamp battery that fits on a keychain and hides its 30-pin connector under a flip cap reminiscent of a Zippo lighter.

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By his own design, though, WALL-E has become, over time, an endlessly curious garbologist who collects objects that strike his fancy -- an eggbeater, a sheet of bubble wrap, a Rubik's cube, a paddle-ball, a Zippo lighter, a brassiere (he experiments with it by putting it over his eyes) a diamond ring in a velvet box (he tosses the ring and keeps the box).

WSJ: 'WALL-E' Is Richly Human Tale of a Robot