to this day I still do not understand how the charger, there is a red button when we want to charge the batteries it should be put right, or middle, or left there with no explanation this button I do not know what it is thank you to inform me I'm sure it's a good product. all the other products I have purchased from amazon gives me entiére satisfaction.je have to date no explanation on the operation of this charger and more unreadable because the record and written in very small characters.