The Rex brandname was used on 1960s Italian made electric guitars (these are not the Rex branded guitars produced by Gretsch in the 1920s). La Bagnini di Roma was a major Italian distributor of consumer goods including musical instruments. They sold in shops and through mail order catalogs using brands including Ariston, Rex and Kroma. The Rex trademark was owned by Ugo Beccacece of Recanati.

Link: Fetish guitars Recanati and Castelfidardo