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Non-magnetic collar are manufactured strictly from non magnetic stainless steel. It mainly used to provide bit weight to drill bit so that drill pipe is in tension. Drill collar can keep drill bit centralized and hole track by large rigidity, which has excellent performance in lower magnetic conductivity, higher mechanical property and resistant to stress corrosion cracking.Customer Options:Standard: API 7-1 or non-standards.Type: Non-magnetic drill collarsMaterial: Non-magneticSize: OD ( 3 1/8 inch-9 1/2 inch ) ID ( 1 1/4 inch-3 inch) Length(10 inch-31 inch)Cold rolled of thread roots.