2-1/4" x 3-1/4" API pin mixer sub / expansion adapter
Used
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.