Its a Sega Speculator which I have had a couple of years now. I don't know anything about it and cannot find any info on the net about this particular Sega model and have never seen another for sale. It works well mechanically but I suspect the electrics could do with some attention soon.
It has a 'Feature' function where you select 1, 2 or 3 to guess if a speculator symbol appears on that reel at which you win 18 coins. Anyway, here are some pics (sorry about quality). If anyone has any more info about this machine I'd love to hear about it.