Copper Drip Tubes for the Trion 707 series. Two tubes are used in the center pan of the 707. The above price is for a set of 2 tubes. These #27 drip tubes are used in the 707U and 707TW and optionally added to the 707 and 707SM. The tubes quiet the not fully atomized water back that drips back to the reservoir. The tube is 1/2" copper pipe 3" long. The tube is flared on one end. The retaining clips are NOT included. We recommend replacing the rust prone retaining clip with a bead of silicone caulk. See the instructions for installing the impeller with a 1/16" gap: Trion Impeller Installation (1 page, 70k pdf).