... API 5DP API standerd (alloy steel E.X.G.S) OD :2-3/8,2-7/8,3-1/2,4,4 ... drill pipe, drill collars and drilling joints (API and other standerds) for more than six years ... of the ISO9001 ,we will get the API citification in the end of the year, ... Satisfy Clients".oil drill pipes:drilling pipeStandard: API 7 and API spec. 5DSpecification: O.D 2 3/8 ... , 3 1/2, 4, 4 1/2, 5, ...