Stacked near the checkout counters, and as colorful as a Fisher-Price toy, it is a not-so-serious-looking power tool: a battery-operated saw-and-drill combination.

"I coaxed him along, calling out words of encouragement, but it was like watching a toy slowly wind down as its battery went dead, " Mr.

Precision spring(compression/tension/torsion/special-shape/battery spring), USB stainless clockwork spring, copper, iron and aluminum rivet, nail claw/claw pearl, and toy axle.