This is a fab bit of kit. Whilst the traditional lapping stick has been around for years and will get the job done, no one has ever said that it's a joy to use. This tool fits in a standard cordless drill chuck and makes lapping valves a whole load easier. The suction cup attached in the same way as with a lapping stick and the body of the tool is held in your left hand and drill is run fairly slowly and the valve is oscillated back and forward just as with the stick, but with far less effort. We have found this tool saves a huge amount of both time and angst.