This is the second combiner unit I've bought, the other was a 6 string eco friendly. The box looks good but check the mc4 connectors as they use cheap ones that don't snap properly so you may have loose connections or no connections at all. I noticed that the 6 string I was using had loose connections, had to replace the single row mc4 connectors and push down while inserting another to keep the connection for a couple of days. I lost half my strength, it confused me a bit until I figured it out. It would also be nice to have holes for grommets instead of holes for cables.