Found this old gem today... Vintage Casio SF-4000 'digital diary' from 1988. Featuring a whole 31,902 characters of battery backed storage. : r/retrobattlestations
Casio SF-4000 Digital Diary PDA (año 1988) - YouTube
Casio SF-4000
CASIO SF-4000 di seconda mano per 12 EUR su Madrid su WALLAPOP
Casio SF-4000 SF 4000 digital diary vintage organizer #3 | eBay