Improvements have been made to the FD67 Series service valves. The primary improvement is conversion from a snap-ring to a captive stem design. Valve stem captivation is done by rolling over material at the top of the brass body. As part of a Poka-Yoke process, the stem cap is also used to ensure that the valve stem has been correctly captivated. Other improvements include use of finer stem cap threads and a change from a crush-type cap seal to a knife-edge seal providing greater consistency in the torque required for the stem cap to seal, the company says.