Perhaps, more than anything, what’s most rewarding about wielding Etón Corp’s Boost 4200 is not the on-the-go charge it provides, but the social kudos you get from being so stylishly prepared.

No waterproofed down jacket with stretchy cuffs and retractable hood can compare since, while we can always pretend to be ambient in freezing temperature, devices are more honest when it comes to displaying the doom that depleting stores presents.

Welcome the 4200mAH lithium battery from Palo Alto’s Etón Corp and you’ll be fast-tracked to a rejuvenated place. The Boost 4200’s micro-USB DC input charges the battery, with a single USB relaying power to smartphones and tablets. Once fully-charged, the Boost 4200 has enough juice to recharge an iPhone 5 twice over.

The charger’s minimal four-dot LED lighting system informs you of the level of charge, a display that’s initiated by a quick tap. It’s this gesture that completely wins people over – enough of a performance to salvage a reputation from your doubters.

Falling within the profile of the 5.1″ x2.5″ iPhone 5, the Boost 8400 comes in at 142g on the scales. It’s weighty but substantial, wrapped in an aluminium casing.

At $60, the price for Etón Corp’s Boost 4200 falls $30 short of the Boost 8400, which offers twice as much capacity, and one more USB output.