There are two insert (ms21209f1-15l)included with standoff
A standoff that must have a threaded end(s) or be internally threaded its full length. For items having external threads on both ends, see stud (as modified). For items with an outside contour that is the same for the entire length, are flat on top and bottom, having internal threads its full length, and the length does not exceed twice the width across the flats or outside diameter, see nut (as modified); use maximum dimensions(s) for compliance.
NSN 7035-01-313-3677
NSN 5945-00-960-7367
NSN 6650-00-597-7313
NSN 5855-01-049-2733
NSN 5998-01-013-5206
NSN 6650-01-355-1271
NSN 5960-00-597-2680
NSN 5915-01-500-5828
NSN 5855-00-149-0766
NSN 6145-01-381-3958
NSN 5920-00-341-6340
NSN 5950-01-435-5478