Replaced the 394 module in my vintage MD-700 to bring it back to life. A bit small by modern standards, but a common men's size in the past. : r/ casio
1988 CASIO MQ-66 Wristwatch, Module 394 Double Calendar - New Old Stock | eBay
Casio Diver 30 BAR MD-900 Module 394 JAPAN made / RARE | eBay
Vintage 1988 Casio MD-501 Submariner 100M Diver Watch, Made in Japan, Module 394 | WatchCharts
Casio MD-709 vintage diver 300 m module 394 | #1056051273