Old International Harvester Wrench #9553DA 2.5 in Gap 18 in Long Yellow Rusty

Description

Old/antique International Harvester/IH wrench -- I originally thought it was for railroads, but have been informed it is for old IH equipment, such as bulldozers, shovel loaders, crawlers and other heavy construction equipment
#9533DA stamped on the handle
Gap is 2-1/2 inches
Length tip to tip is 18 inches
Very rusty; has not been cleaned for patina.
Still can see the number clearly and that it used to be yellow
Very heavy; weight is just over 6 lbs