I have purchased the pump to install an AC. Problem was that the AC came with a SAE 5/16 thread and the pump is SAE 1/4. Also the instructions are not very clear. Nice: it comes with more than enough oil, just make sure you don't overfill, the gauge glass for oil is in the front. I ended up buying an additional 1/4-5/16 hose to accomplish the task. Also the gauges only measure pressure, so you need an additional tool to measure the vacuum.