This is a replacement union. If for some reason your union gets damaged or lost, here is a replacement union. ALL OF OUR PRODUCTS COME WITH A DRYER SIDE UNION AND WALL SIDE AS A SET, DO NOT ORDER THIS IF YOU ARE ORDERING ONE OF OUR COUPLINGS. This Dryer Side Union is found on the MV-90 and MV-180, but will also work with the MV-Flex if trying to convert an MV-Flex installation to a MV-180 self-aligning style. It has a 12 inch piece of UL 2158A flexible duct factory connected to the ring magnet.