This Casiotron S-15 is released way back in the 1976 when Casio first released their lineup of digital watches! Such a joy everytime I wear this watch! : r/casio
Casio Casiotron Vintage Men's Watch - Etsy
CASIOTRON X-1 (1977) : r/casio
Casio Casiotron S-12 – My Retro Watches
Vintage Casio collection and Casiotron series and model numbering | WatchUSeek Watch Forums
Vintage Casio CASIOTRON 02-504, QW.02 Japan Liquid Crystal, Year 1976 | eBay
The Casio Vintage Club | Casio Casiotron 01-501(01), release date 1974 November, this is the debut model, the beginning of Casio wrist watches, the very first model
Vintage Casiotron Digital LCD | Casio watch, Vintage watches, Digital watch