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www.toboc.com
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square kelly
Specification:2-1/2" 2-7/8" 3" 3-1/2" 4-1/4" 5-1/4"
Kellys are the drive section of the whole drill stem.The manufacturing of the products refers to the standard of SY/T6509-2000 or API SPEC.7-1.AISI4145H alloy steel is used ...
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