Reassuringly, to have one.

I bought the part prophylactically and placed in the glove compartment, in the event that I ... must reload traveling times a eGo battery, my cell phone, tablet, speakers or my partner complains of strong battery consumption of your phone.
Of course, I have power via the cigarette lighter .. but if the fuel is all, or I want to leave the car? ;-)
The workmanship is very good. Nothing knarrzt, all bombproof. The four blue LEDs indicate when you connect an external load short on battery status information.
The small built-in LED is a real added value - although not a substitute flashlight but is bright and helpful. The on and off switch is slightly recessed into the casing, so that an accidental turning on is virtually excluded.
Included is a slightly padded carrying bag.

Absolute buy recommendation.