American Standard ball rolling thread less susceptible to shear forces and require less friction torque.

Rolling Thread can also benefit long-term. To save space parallel to the valve can be made compact, short structure. These three way ball valves are sometimes referred to as "clip-gate" in this, "WAFER", is used to mean "thin." These valves are not as literal as lazy thinking sandwiched between two pipe flanges. But the flange machined directly on the boring body length of the valve is reduced. Flange simply refers flange, stud or bolt and nut with two nuts can not be used.
For those who have not may disassemble the valve assembly, the American Standard ball valve connecting surface can be equipped with studs, you must use the substitutability of bolts.