Casino history lives in the objects people handled: cards, roulette wheels, and...

https://online-wiki.win/index.php/What_Does_It_Mean_When_a_Slot_Keeps_Reels_but_Changes_the_Mechanism%3F

Casino history lives in the objects people handled: cards, roulette wheels, and slot reels. The shift from single-zero to double-zero wheels shows how a small mechanical change could shape play, odds, and the experience of a night at the tables.