OS&Y Outside screw and yoke gate valves are recommended for service indoors and in pits outdoors. They are not recommended for throttling service. The stem indicates at a glance whether or not the valve is open. Smaller sizes, 3⁄4 through 2 in. NPS inclusive, are of bronze. Large sizes, 2 1⁄2 through 14 in. NPS inclusive, are of iron, bronze mounted. One manufacturer makes valves of bronze up through the 3 in. size. Unless otherwise noted in the listing, these valves have 175 psi (1205 kPa) rated working pressure.