The Efest Slim K4 Quad Bay Battery Charger is a high quality, cost efficient, portable charger capable of charging 4 cells at any one time. Featuring Micro USB allowing for 1 amp charging (1 amp x 2). Each battery bay is monitored independently to provide an efficient charge of each battery. There is an LED indicator to show the current charge level of each battery. In build into each charger is a range of protections to promote safer battery charging. Included protections are reverse polarity detection, overcharge protection, short circuit protection, amongst others. A great charger for everyday use and perfect for those trips away in thanks to its small size and quality design.