For drilling 28" irrigation wells, elevator shafts, and other large diameter holes in clay and other geological formations.
Supposedly the "cross" or "star" with the 4 cutting edges helps bits like this drill straighter in slanted formations.
Although a special purpose bit, drillers could use it every day in some geologies and conditions.
Presumably American manufactured with carbon and/or alloy steels, but unsure if this is Acme, Spang, Gill Rock Drill, Ideco, Trident, Rampp, O.W.S. Co., Keystone or maybe another historical tooling manufacturer.
If you require thread protector(s) on tool joint(s) add another $15.