Whale - Seaward Thermostatic Mixer Valve - WX1599B. Plumbing "safety fitting" for the Whale "Quick Connect" system. Thermostatic mixer valve using three 1/2" BSP Male threaded ports.. Constructed of nickel-plated brass including non-return valve. Each BSP running thread is fittted with O-ring.. WARNING: This product can expose you to chemicals which are known to the State of California to cause cancer, birth defects or other reproductive harm. For more information go to P65Warnings.ca.gov.