4" female camlock (cam and groove) X 2" male camlock (cam and groove) DA4020. You will receive one 4" female camlock X 2" male camlock. This adapter is used for connecting trash pumps and vacuum trucks to suction hose assemblies and discharge hose assemblies. There are cheaper product brands available, but we offer this heavy duty version for a great price. Light weight, a must have for any shop.