This is very nice, like new 1/2-14 NPT pipe tap marked "1/2 NPT 14 BUTTERFIELD DERBY LINE VT. MADE IN U.S.A. HS8 FOR STEEL" on the tap shank, or BUTTERFIELD DIVISION of UNION TWIST DRILL Co. This tap is vintage, but in very good shape, most likely was not used as the original paper thread covering and oil is intact.
A hard to find vintage tap, with the engraved lettering on the shank, rather than the newer etching type markings. Made to be used on steel.