They don't really come any bigger than IGT. International Game Technology boasts around half the slot machines in US casinos, and their online output is impressive enough to suggest the developer isn't just a land-based player. In fact, there are few slots manufacturers around today that have so completely cornered both live and online markets.
The slots world was shocked by the firm's takeover by GTECH in 2014 but it did nothing to change the reputation of a firm that's undergone many alterations and takeovers but has remained a major player across the world.
From popular land-based slots (some times called Vegas Slots) to the biggest progressives around, and online slots that keep the welcome bonus hunter occupied, things don't look like slowing down anytime soon for IGT.
IGT started out life as A-1 Supply, developing video poker and blackjack games, and slot machines. Founder William "Si" Redd changed the name to SIRCOMA (an abbreviation of Si Redd Coin Machines) and went public as International Game Technology in 1981.
Incredibly, sales of the firm's machines rose from a few million bucks in 1975 to over $60 million just seven years later, IGT boasting about 90 percent of the video gaming market in Nevada.
It wasn't until 1986 that IGT's technological revolutions sent the company into the stratosphere.
The firm developed the Player's Edge Video Poker machine as well as one of the first microprocessor-operated machines - the S-Slot - while also investing in lottery ticket terminals in some US states.
By the late 1980s, IGT controlled the market share and celebrated its position by introducing the Megacbucks slot machine in 1987. The world's first progressive jackpot slot allowed players to connect across networks and multiple casinos to create some truly 'mega' jackpot prizses.
In the late 1990s, IGT focused its attentions on the British market with a buyout of Barcrest Gaming, in one fell swoop snapping up the giant of the UK fruit machine market.
The 2005 acquisition of WagerWorks provided IGT with the platform it needed for the growing online slots market. It enabled the US player to bring a lot of its popular land-based slots to the online casino world.
But amid an era of takeovers and mergers, it was the giant's acquisition by Italian tech firm GTECH in 2014 that really caught the attention. The sale went through for $6.4 billion (made up of $4.7 billion cash and $1.7 billion of debt).
Let's get down to the business; when it comes to some of the most popular slot machines around, IGT titles are up there.
Wheel of Fortune, and its many variants and upgrades, features a real-life spinning wheel atop the slot machine which is triggered by lining up special symbols on the reels.
Taking the 'wheel' bonus to another level, however, is the big-brand video slot based on the hit Hollywood film, Sherlock Holmes.
Featuring five reels and 30 paylines, actual characters and video footage from the Guy Ritchie-directed film accompanies the play. The wheel spin bonus awards progressive jackpots galore and $1 million payouts are not uncommon.
Five Cleopatra symbols on a payline triggers a 10,000-line bet jackpot, while a free spins bonus awards 15x multiplier.
Da Vinci Diamonds, meanwhile, is the online slot that casinos never tire of using to attract new real-cash depositors. The game features IGT's trademark 'Tumbling Reels' where winning combinations disappear to allow symbols above to fall into their place. In both land-based and online casinos, the Da Vinci Diamonds Dual Play format features two game screens where symbols 'tumble thru' the top set of reels onto the bottom one.
Elsewhere, IGT's Multiway Xtra range of slots like Siberian Storm offer something different - and 72- possible paylines - but newer slots like Bubble Craze have tapped into a desire from slots players to see something a bit different in the lobby.
One of a new breed of arcade-style slots, Bubble Craze is played over a honeycomb-style set of reels where 'bubbles' rise from the bottom to form connecting paylines.
Where do you start but with Megabucks? Developed in the 1980s as the first progressive jackpot 'wide area' slot machine to carry a $1 million jackpot, it quickly became popular with slots players across the US.
The game has been responsible for some ridiculously big winners, but perhaps none bigger than the software engineer who bagged a $39 million jackpot in 2003 playing at the Excalibur casino in Las Vegas.
IGT is just about slots. In 1997 the firm introduced its 'MegaSports' system that allowed sports bettors to gamble on sports in Vegas more efficiently. At the same time, it devised computerised systems to keep track of gambling activity on every game in a casino and award personalized bonuses to players - a first.
In 2000 IGT brought out its millionth machine and developed the innovative 'MultiPLAY' machine which allowed players in casinos to play up to four video slots at the same time.
More recently, IGT has attempted a move into the social gaming market with its DoubleDown Casino app. The social casino, available through Facebook, boasts over six million players and features some of the developer's most popular slots like Siberian Storm and Cleopatra. Video poker, blackjack and roulette are also available as part of the Player's Suite.