Radio Shack EC-21 Handheld Electronic Calculator, Blackjack | Smithsonian Institution
File:Vintage Radio Shack Blackjack 21 Combination Blackjack and Electronic Pocket Calculator, Model EC-21, Catalog No. 60-3011, Made in Taiwan (12109795754).jpg - Wikimedia Commons
BlackJack Calculator Download - Is much more accurate and faster than the online version