Caldera Diverter Valve Handle Gray Spa Hot Tub Caldera Diverter Valve Handle in Gray. Measures 9'' x 6'' x 1'' This Diverter handle Slides on the Diverter Valve Stem that measures about 7/16" and is used to operate the Diverter Valve and is for Caldera spas by Watkins Products only. Hot Springs Spas Caldera Diverter Valve Handle Gray Spa Hot Tub Hot Spring Spa Supplies carries spa fragrances, air & water valves, control systems, filter accessories, lights, cleaners, pumps, thermostats, and more for virtually every hot spring model.