This is a very good, clean double open ended lock nut wrench marked "THE BILLINGS & SPENCER CO. HARTFORD CONN. U.S.A. 1356 7/16 USS 3/8 USS". Keep in mind that the USS designation is bolt size not actual measured size, in other words the 3/8" measures 11/16", and the 7/16 USS measures 51/64" actual opening. It is 6.8" long overall, and has the very thin (3/16" thick) heads. It's in nice shape, little wear, no damage, no rust, a little minor pitting, and a few dings along the edge of the 3/8 USS end. A rare thin head wrench!