LengthSpecified by Tool NumberMaterialSteelPurposeTo provide extension to oil hole drills and reamersUsed WithOil hole drills and reamers, 5JDT 65-1004-1, 5JDT 65-1004-2, 6JDT 65-1004-1, 6JDT 65-1004-2External Threads 9/16-18 UNF-2AInternal Threads9/16-18 UNF-2B