The name depends on which keno you are watching
Walk into a casino lounge and you might see a clear plastic dome full of numbered balls bouncing on a jet of air. Sit at a bar and you might see a screen that simply lights up twenty numbers. Both are keno, and the machine doing the drawing has a different name in each case.
The mechanical device with the balls is called a blower. The electronic version is a random number generator, often shortened to RNG. The same split exists across many casino games, but keno players notice it because the two formats look nothing alike and the pace feels completely different.
Neither name is a brand or a model. Blower and RNG describe how the numbers are produced, not who manufactured the equipment. A venue may use one, the other, or both in different parts of the floor.
How a keno blower works
A keno blower holds eighty balls, numbered 1 through 80. Air circulates inside a transparent chamber so the balls keep moving and mixing. When a draw begins, the machine releases balls one at a time through an opening. Each released ball is read, displayed on a board, and logged. The process repeats until twenty balls have been drawn.
The transparency is the point. Players can watch the balls move and see that a ball is not being selected by a hidden mechanism. The physical mixing and the visible release are the entire security story for this format.
Older keno games used a different method. Balls sat in tubes, and a hand-cranked or motorised cage tumbled them until one dropped out. Some venues still call any ball-drawing device a cage even when it is a modern air blower. The word has stuck around as a generic term.
How an RNG keno machine works
An electronic keno game replaces the air chamber and balls with software. The machine runs an algorithm that produces twenty numbers from the 1-to-80 range for each draw. The algorithm is the random number generator.
The player sees the result as a grid of highlighted numbers on a screen, often within a second or two of pressing play. There is no physical ball to watch, which is why the pace can be much faster than a blower game. A blower draw takes as long as the balls take to release. An RNG draw takes as long as the software takes to compute, which is effectively instant.
An RNG does not mean the game is rigged or loose. It means the outcome comes from a mathematical process rather than a physical one. Independent testing laboratories commonly certify RNG behaviour, and that certification covers the game mechanics, not the operator's financial conduct.
Blower versus RNG: what changes for the player
The two formats produce the same game structure: eighty possible numbers, twenty drawn, payouts based on how many of your chosen spots match. What changes is the experience, the speed, and where you find each format.
| Feature | Blower keno | RNG keno |
|---|---|---|
| Draw mechanism | Air-mixed balls released one at a time | Software algorithm selects twenty numbers |
| Draw speed | Set by physical ball release | Near-instant |
| Where it appears | Lounge areas, dedicated keno counters, some live draws | Bar-top machines, video terminals, online and mobile play |
| What the player watches | Balls moving in a transparent chamber | A screen highlighting the drawn numbers |
| Verification method | Visible physical mixing | Testing laboratory certification of the RNG |
The house edge on a keno bet does not come from the machine type. It comes from the paytable, which sets how much a given number of matches pays. The same paytable offered on a blower and on an RNG carries the same mathematical edge for that bet. The machine changes the delivery, not the arithmetic.
Other names you might hear
Keno equipment attracts a lot of informal vocabulary. A player might call the blower "the bubble machine" because of the dome. A casino employee might call it "the air mixer." A video keno terminal is sometimes just called "the machine," which is confusing because the same word is used for a slot cabinet.
In some venues, keno is not drawn on the floor at all. A central system runs the draw and broadcasts it to screens around the property. The player buys a ticket at a counter or kiosk, and the numbers appear on monitors. The device running that central draw is still either a blower or an RNG, just located out of sight.
Online keno is always RNG-based in standard play. Some live-dealer studios stream a physical blower draw, but the typical online keno game is a software draw with no physical balls anywhere in the process.
How to check which machine a venue uses
If you are watching a draw in person, the answer is usually visible. A transparent chamber with bouncing balls is a blower. A screen that fills in numbers without any physical draw is an RNG. If the draw is broadcast from elsewhere, the venue's keno information page or the game rules screen will state the draw method.
For online play, the game's information panel is the place to look. It will describe the draw as an RNG outcome and may name the testing laboratory that certified it. That panel is also where the paytable lives, and the paytable matters more to your expected result than the machine name does.
Keno is a high-house-edge game relative to most table games, regardless of the draw method. The machine name answers a practical question about what you are looking at. It does not change the long-run mathematics of the bet.
FAQ
Is a keno machine the same as a slot machine?
No. A slot machine spins reels and pays on symbol combinations. A keno machine, whether a blower or an RNG terminal, draws twenty numbers from eighty and pays based on how many of your chosen numbers match. They share cabinet designs in some venues, which is why the two get confused.
Do online keno games use a blower?
Most do not. Standard online keno runs on an RNG, so there is no physical ball draw. A small number of live-dealer studios stream a real blower draw, and those games will say so explicitly on the table or game screen.
Why does the keno machine draw twenty numbers?
Twenty is the standard draw size for keno. The player marks a set of spots, and the payout depends on how many of those spots appear among the twenty drawn numbers. The paytable shows the return for each possible number of matches.
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This article is general information about how these mechanics work. It is not legal advice and not a recommendation to gamble or to use any particular operator. Availability and legality differ by jurisdiction — check the rules that apply where you are.