Some folks regularly use up their phone batteries halfway through the day and need to carry around a large (and heavy) portable charger with a lot of capacity. But for others, a little boost may be enough. Meet the Revi charger.
The credit-card-sized device, which is available with either an Apple Lightning or a micro USB connector, comes in two capacities. The 550 mAh charger weighs a mere 1 oz. and measures 3.3 x 2 x 0.01 in.; the 1,440 mAh Revi weighs 1.7 oz. and measures 3.3 x 2 x 0.28 in.
Just pop it in your wallet and you're good to go.
Price: $25.00 (550 mAh) or $30.00 (1,440 mAh)
Shipping: Summer 2014
Update: When I wrote this article, the Revi Charger was supposed to ship during the summer of 2014. As of April 2015, the product is still not available, although the company website says it should start shipping Spring 2015.