Note: The following is part of our roundup of B-C battery packs. Go there for details on how we tested this device.

I was able to get my hs on the Tronsmart esto 12000 Type C charger, despite the fact it seems to be discontinued. The company is now advertising the similarly-priced Tronsmart esto 10400 ($27 on Amazon) in its place.

A quick look at the specifications of the smaller capacity version, it appears the two chargers are identical in output charging specs. So with that in mind, I’ll review the 12,000mAh (45.12) version as if it were the 10,400mAh version.

The slender size of the esto makes it easy to throw in a purse or small bag for an overnight trip not really notice you have it on you.

A power button is found on the left side of the unit, four indicator lights on the top that light up any time you plug something in to it.

Two ports are found on the front, a B-A port that’s QC 3.0 equipped (although Tronsmart makes it clear this pack will not work with the HTC 10), a B-C port that doubles as a charging port for the pack itself along with a gateway to charging your phone.

Testing the capacity of the pack, I measured it at 80.17 percent efficient, putting out 36.17 of power, placing it at the bottom of the packs we tested.

Charging time is the saving grace for a such a small pack, with total time to recharge the esto coming in at only 3:10.

Included in the box with the charger is a B-C cable.