Havemeyer rebar

Bars are deformed in a manner that does not change the net cross sectional area along the length, thus producing a bar where the entire cross sectional area all along the bar carries the tensile load. These bars weigh less per foot than other bars of equivalent strength.

Patent from 1909: https://patents.google.com/patent/US1151947A/en

Sold by The Concrete Steel Company of New York