This light has some potential, I’m gonna be receiving this pretty soon. Hopefully it can be water resistant and have a 17mm driver.
Looks interesting but expensive considering the gold color Kmashi power bank and flashlight posted about earlier is about the same price on Amazon and includes the batteries, though not removable. This one does have a removable head, possibly useable on other power banks and ports, but it is single mode while the XTAR UL1 designed for use with any power bank or USB 2 or later powered port is much more versatile with it’s multiple modes it appears to me.
I knew I should have done a review on these.
I’ve purchased two versions of this light recently, and I wasn’t happy with the black one at all. The flashlight aspect of it, the color temp must easily be 8000k or higher, and is all flood.
Now, this second version I purchased, has a proper beam profile (mostly beam, some flood) and color temp is no more than about 6000k.
Other than the above issues, both work perfectly using an AW Protected flattop cell.
Mini USB Light Black Version - Due to improper white balance, you can’t see how cold the hot spot really is. But still a nice
emergency USB charger.
Mini USB Light Silver Version - Much better as a flashlight when not needed as a emergency charger.
If messing with USB lights and power boxes this may be useful.
Basically a LCD display USB power meter that can read out Volts, Amps, Watts, capacity in mAh, total capacity in mAh and time connected. A very fancy Charger Doctor with added capabilities and LCD display for easier reading in sunlight.
I am seeing direct USB powered lights for sale on ebay and Amazon which are claiming outputs up to 2000 Lumens. Typically these are using XM-L T6 LEDs so I downloaded the XM-L LED data sheets. At 1000 mA to the XM-L T6 LED output will be circa 388 Lumens and at 2000 mA the output will be circa 692 Lumens. This is LED Lumens out with no circuitry losses so you can see how truthful the manufacturer and seller claims are. Circuitry losses combined with reflector and lens losses in the light will reduce the theoretical output by at least 25% and only actual Out The Front (OTF) Lumens are of any use to the user.
No normal USB port is going to put out much more than 2 Amps and then only from a power bank or high power wall wart. The measured highest I have seen one of these lights actually draw so far is 1.1 Amps and this is a bicycle light that claims 1200 Lumens out. I figured with circuit and reflector/lens losses a genuine 300 OTF lumens is probably about the maximum possible for this current draw from this light or 25% of the claimed output.
Just be aware of how exaggerated the claimed outputs can be for the more powerful of these devices. I have one light measured by RMM to put out 2000 Lumens maximum so if I ever get a USB light that comes even close to being as bright I will have a direct comparison light available. Of course no USB port or wiring could support the needed current for such a light. 
JohnnyMac just posted a review of a combined single 18650 power bank and flashlight from Powertac, their E8. Four modes from a 1 Lumen firefly mode to a 388 OTF measured Lumens high mode. Not cheap but the highest power light with integrated USB power supply I am aware of. Of course with this combination the light is not limited to what a USB port can provide as the port is an add-on to an 18650 powered flashlight.
Here is the link to the makers web site. Not on Amazon yet that I could find.
http://powertacusa.com/index.php?route=product/product&product_id=241
http://www.fasttech.com/products/0/10002784/1484400-enb-1a-1-2-3-18650-li-ion-battery-usb-emergency
I just received this one linked to above. Not bad if you can live with the listed 1 Amp out power limitation but with 3 high capacity 18650 batteries it theoretically is close to 10,000 mAh capacity. Also the flashlight is relatively bright even though only two modes out, flashlight and low frequency flashing. Cooler output than the Kmashi but similar overall light level in a less focused beam, so a larger hot spot.
Takes a firm grip and pull to separate the grey and white parts to install or remove the batteries.
Chinese Lumens claims have not improved in 4 years, just gotten worse. They are now claiming 2000 Lumens for USB powered light heads and direct drive from USB power bank bicycle lights. Also they are now claiming 9900 mAh capacity for junk 18650 batteries, actual tested capacity about 1000 mAh. Even Chinese sellers on Amazon. If I do some Amazon reviews of their stuff then they are going to be very unhappy sellers. I wish Amazon would put a stop to this crap being listed.
There are currently about three USB powered light heads that plug into a power bank for their power I found on ebay and Amazon that look good. Machined and anodized aluminum construction with 3 or 4 output levels. I have ordered units and will report on them once they arrive.