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Casing hanging sub-threaded (mandrel type), Kawa two categories;
Kawahl-type hanger: G-type, W-type, WD-type, WE-type, and so on;
WD-type hanger for connecting the casing head and surface casing, which by external force to make the teeth clasp teeth casing;
W-type hanger is the casing to strengthen the structure of self-sealing;
WE type and G type manual reinforced seal structure.