This is an adapter to convert the proprietary dust collection port on Dewalt tools into a size usable by standard vacuum hose accessories. The adapter clips onto the tool to hold securely in place and prevent rotation. The outlet has a 1.2" inner diameter designed to friction fit with the Powertec 70175 dust collection hose available on Amazon. It will also fit with a universal power tool adapter to connect a 2.5" hose.