Operating mechanically, Double Block and Bleed Service Valve features secondary ball/sealing surface to retain pressure in event that first ball or sealing surface is damaged. Rotating base lets users adjust position of handles to either open or close valve by rotating valve itself into correct position. Weighing 56 lb and operating at temperatures up to 450°F, depending on stem and seal material selected, valve meets NACE MR0175 and NACE MR0103 requirements.