... oil underground, it is connected to the sucker rod and drive by pumping unit to move up and down.In ... uper pressure, then the fluid will be forced to go through the stationary valve and flow into the ... , then go into the tubing,Testing:1, Conform to API Spec 11AX2, All the accessories of the sucker ... fast, smooth or not5, all the materials conform to the drawing and request.Features:1, The sucker rod ...