Required for both JohnDow oil filter crushers. Of course, these units are powered by air. If you want to protect your investment, and help it last much longer, you should get this accessory. It will keep moisture from builing up in your tool, and will also help keep it lubricated. So many maintenance and repair issues could be avoided on this type of equipment if it were just properly maintained. If you already have one of these running in-line with your air source, then you're all set.If not, we highly recommend this one.