Provide precision flow control and full shut-off in one flow direction and automatically allow unrestricted free flow in the opposite direction
Two-step needle provides fine adjustments at low flow with the first three turns of the adjusting knob, the next three turns give full-open needle position and conventional throttling control
When flow is reversed, the heavy-duty poppet/retainer permits full flow return capacity
Exclusive color-coded reference scale on the adjusting knob greatly simplifies flow setting, resetting, adjusting and return to an original flow
A simple set screw locks the valve on any desired setting