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 S-12 – My Retro Watches
Casiotron 38CR-12 donor project and second revived module. | 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
CASIOTRON WATCH | Casio watch, Casio, Watches for men
Casiotron TRN-03 Mod. 1670 1979 Digital Watch JAPAN for NZ$149 for sale from a Seller on Chrono24