I was worried about this being a true 10,000 mAh capacity.So many are much smaller than their claims.This appears to be correct and very reasonably priced.I've been running an Opolar 8" USB fan that draws about 350 mAh for about 10 hours and the capacity meter says it's at 58%.That's pretty darn close to what I would expect.It also chargers at 2 amps per hour,quicker than my current power bank that only charges at 1 amp...Looks like a great value.For camping and emergencies it has a large capacity for doing multiple cell phone charges or use with usb fans and tablets.