Worked really well initially. Only a few months old and the indicators on this device have failed. The charging has become slow and the best part is that I haven't used it too often either just about twice a week). Now buying a CoolNut!!I guess this product was imported and therefore would be difficult to claim warranty.

Open the simple cardboard packaging to reveal a 5" x 3" and 3/4 of an inch deep battery in quite smart but tough gold and silver plastic. In terms of weight it comes in at 240g which to put this in context is relatively quite light - an iPhone 6 or Samsung S4 is 133g without case. Certainly small enough to carry in a back-pack or bag, and with enough power for a weekend away.In terms of output (to charge your phone or tablet), this is 2 USB sockets, so you've the option of charging power intensive devices (eg. an iPad) using the faster 2.1A rate, and charge a smartphone using the 1A port at the same time.Nice to see the ubiquitous 4 LEDs to indicate how much power it has left, and each counts down in 25% units from 100% to zero as you drain the battery. There's a single micro-USB socket and a short cable to plug into your existing smartphone charger, although at this size, you'll need to leave it charging over night.Finally, this charger comes with a short (6” long) USB to micro-USB cable so you can charge it.Does it work?------------------Yes. I tested it with a USB Power meter, and in addition to being auto-sensing (it detected my iPad could draw more power than my iPhone so produced it automatically), it was also pretty efficient when compared to my home wall charger which is pretty impressive.Charging an iPad I received the following:-Home Charger This device5.09 volts 5.1 volts2.32 Amps 2.26 AmpsIt also charged my wife's iPhone 5S from absolutely flat to 100% in around 90 minutes.The battery is rated at a 10,400 mAh which should recharge most smartphones several times. To put this in context, here’s the battery size of a range of smartphones:-* Google Nexus 5 - 2,300 mAh* Samsung Galaxy S3 - 2,100 mAh* Samsung Galaxy S4 - 2,600 mAh* Samsung Galaxy S5 - 2,500 mAh* Samsung Galaxy S6 - 2,600 mAh* Apple iPhone 5 - 1,400 mAh* Apple iPhone 5S - 1,570 mAh* Apple iPhone 6 - 1,810 mAh* Apple iPhone 6 Plus (Phablet) 2,915 mAhYou never get 100% power out of these devices (typically around 70% is acceptable), but you should get about 4-5 charges for a Samsung Galaxy or an iPhone 5S.What's Good about it?-----------------------------* Two USB output sockets means you can charge two devices at once* Sizable power bank - lots of power for the entire weekend* Beautifully small and light - means you could carry it in your bag without noticing itWhat you should be aware of----------------------------------* It doesn’t come with a wall charger or USB to iPhone cable (but these devices never do).* It doesn’t come with a built in light or carry case (which would be handy to carry your cable and power bank together).Overall Opinion---------------------Build Quality: 5 StarsDesign and features: 4 StarsValue for money: 5 StarsConclusion-------------Small, well built and powerful power bank - great power to weight ratioHighly recommended.Disclosure: While I did receive this device in return for an unbiased review, I was not paid a penny, and no attempt was made to influence me. These are entirely my personal opinions, and to misquote Groucho Marx - “These are my opinions, and if you don’t like them, I have some others”. ;-)