To start with, when I inspected the pump, all the head bolts were loose and one was sticking out about an inch. I emailed the seller about torque settings and they said to tighten them. Made me question if the pump would explode when I brought it online. Fortunately after getting it running it is a quiet pump and builds air and recovers quickly. For the price, a good buy, but check the tightness of ALL the bolts prior to installing it. Gave it four stars for the quality control issues.