2 X 2 INCH HEATER SEALS Commonly Used with : 2 inch Heater Tubes. Balboa, Gecko, Hydroquip, RMF, Brett Aqualine. Dimensions: Approx thickness: 5mm overall Diameter: 75mm external If you require a wrench to take off the Heater Union rather then breaking it, please check out our Hot Tub Heater Union Wrench .