I found the oiler well made and worked without any leaks. Following the instructions, filling it with a pointed oil bottle was easy. Unfortunatly I ordered this tool after completing my backyard project so the test consisted of shooting a few 3" nails @ 110 PSI and I had no issues. After the three round burst I noticed that the oil level changed a small amount indicating it was dispencing oil into my air tool. Not sure if contractors use these, but if so I can see having several filled and standing by for large jobs. I'm very satisfied with this purchase.