21

The 1935 Rock-Ola Manufacturing Corporation's "21" pinball machine (manufactured May 1935) is a piece of early electro-mechanical (EM) pinball history. It was later reissued as Rock-Ola's '21,000' using higher score values.

Gameplay on the "21" is characterized by a relatively straightforward layout. A solenoid kicker positioned above the bottom free play hole kicks the ball back into play, giving players an extra chance at scoring. Notably, the factory power supply was a 6-volt battery, though surviving examples have sometimes been converted to line power.

No information is available on the designer or any specific artistic or thematic elements of the "21." Its age and relative rarity make it a fascinating piece for enthusiasts seeking insight into the early development of pinball design in the 1930s.