Purge, and Needle Valves Hansen's specially designed Gauge, Purge, and Needle Valves feature tough, forged steel bodies, compact size, and polished stainless steel stems. Their patented o-ring plus packing dual-seal design and polished stainless steel stems provides leak-free packing. The safety stem design prevents removal of stem from body or stem "blowout". A Long Neck ® version is available that provides extra clearance for gauge-turning rotation. They are available in 1/4 " or 3/8" MPT or FPT globe or angle sizes and styles. Hansen's Gauge, Purge, and Needle Valves are available with seal caps, bar handles, or bare stems. Often used to isolate pressure gauges on regulators, these valves can also be used to pump out, purge, and meter refrigerant liquid or gas.