I just bought this unit based on good reviews from a fellow camper and it looks like it is good quality out of the box but I had a problem at step 1: remove the side service panel to add oil. There is a knob on the panel with directional arrows. I turned the know from tight to looser and finally removed it all together. The side panel it is holding in place is still firmly in place regardless of whether the knob is on loosely or off entirely. If anyone owns this invertergenerator please tell me the secret to removing the service panel : ) I've added photos of the panel and knob.