At an all-time low price of $23, these multitasking gizmos offer hours of heat — plus they can keep your phone juiced up.

If you're over those squishy, shake-activated hand warmers and want something a little more high-tech for those chilly ...

To enable this, [Greg] 3D printed a small crate with plenty of vents, into which he stacked six hand warmer sachets. An egg was nestled in the center – a perfect choice as it can be cooked in ...