... )material class:AA-HHIn petroleum and natural gas extraction, a Christmas tree is an assembly of valves, spools, and fittings used for ... .Specification level:PSL1-4,6.Performance Level :PR1-27.The Christmas tree refers to all the devices on the tubing head and ... differently so as to meet the different requirements.9.The Christmas tree could be used for oil exploration, gas exploration, water adding ...