I bought this to be able to charge my TomTom one v4 at home. It will charge it from almost flat to full in just over an hour. It is also used to charge my Samsung camera and will charge faster than the standard Samsung charger(400ma)without problem. The unit is well made. It has a small red led on the top to show when it is switched on. The unit gets slightly warm when charging, but seems to have an electronic control to limit charge when the battery is charged. I put my TT on charge and forgot about it for several hours;when checked, the unit was cold, so had obviously stopped itself from charging. The service from iBox(the seller)was excellent as usual and I purposely looked for it in their listings as I have had good service from them before.