CPC Subgroup
E21B 17/07 Telescoping joints for varying drill string lengths; Shock absorbers
Full Title
Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Casings; Tubings > Couplings; joints > between rod and bit or between rod and rod > Telescoping joints for varying drill string lengths; Shock absorbers
2 direct subcodes
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