The christmas tree is mainly composed of plate valve, choke valve, small spool, upper flange, christmas tree cap, pressure gauge, globe valve and other parts. The structure can be selected according to the needs of single wing, double wing structure. 2. Generally, the choke valve adopts needle structure. 3. Plate valve can choose PFF, FC, FL, FLS and other structural forms. 4. All pressure gauges are aseismatic.