This is a very nice vintage box combination wrench marked "WILLIAMS 11/16 SUPERRENCH U.S.A. 1171". It is 16" long and the actual measure size of the opening is 1.06" which is confirmed as correct opening size for a 11/16" machine nut/bolt head.  This was an identifacation standard that was used for some applications during this era.  It can become confusing at times. This is a very sturdy wrench with the bar measuring .30 x .84" wide. This model has an industrial chrome finish which is about 90% intact, no rust, some minor dings and scratches. The overall condition is good++ both ends very good, minimal wear. From the 1930's-40's era, by a well known quality cast steel hand tool maker, Williams!