The unit is outside entirely of plastic, but makes a stable impression. The connections are provided with tight springs, so that each contact of the inserted batteries is kept and clean. The battery is tested ert, then loaded the status you get on the LED for each channel displayed. A simple device with no frills at a reasonable price. Functional and priced the limits are in the charger so much higher, so for in the league at 100 a processor-controlled multi-charger. The only thing that the devices can do more than this one, is to go and discharge cycles an automatic refresh cycle per channel. Worth it for me because I can buy a lot of battery packs for the price gap between the loaders and so many I did not. All in all, in the price range absolutely ok.