It's fine if your expectations are realistic
Look, it says that it will fully recharge a smartphone, which may or may not be true, depending on what smartphone you have. An iPhone 4 battery has a 1420mAh capacity. The Brunton Pulse has a 1500mAh capacity, so should fully charge an iPhone 4. However, an iPhone 6 Plus has a 2915mAh battery, so the Brunton will only charge an iPhone 6 Plus up to around 50%. See? And that assumes ideal charging conditions (cold temperatures will reduce the charge) and that your phone is turned off - if it's left on it'll be using power as you charge, obviously. With that in mind, the previous reviews are a little unfair. However, manufacturers of these things are still prone to the occasional exaggeration, and in my experience the 1500mAH capacity doesn't quite equate to 1500mAh of charge. That said, because the Pulse is slip and has the cables I need built in (I use an Android phone with a standard micro USB port), I use it all the time, mostly just to top up the charge on long days out, but I've also used it while camping to charge my Sony Z3 Compact (2300mAH) from 50% to fully charged over night. So, a neat little gadget - just don't expect it to do more that it can (and maybe, with smartphones becoming increasingly powerful and their batteries bigger, Brunton should revisit that "1 full smartphone charge" claim).