THIS IS AN ALLIED MACHINE & ENGINEERING SPECIAL SPADE DRILL HOLDER, MODEL 6504-4137. ITS OVERALL LENGTH (OAL) IS 9.5 INCHES, FEATURING TWO FLUTES. THE FLUTE LENGTH MEASURES 6 INCHES, AND THE SHANK LENGTH IS 2.75 INCHES. BOTH THE SHANK DIAMETER AND THE DRILL END DIAMETER ARE 1.25 INCHES.