That's SCSI to SCSI. That's to use a 2.5" SCSI drive in a 3.5" SCSI bay. The question everyone has is where to get something which allows one to connect a CompactFlash card to a SCSI bus.
I've used various adapters, and although I'm repeating myself it's worth emphasizing: a cheap adapter will likely cause problems with various machines (if connected to a machine's PCMCIA or IDE bus), or will likely cause problems with a SCSI-IDE adapter if connected to one. I've tried many kinds. The only kind which works wherever I connect it and with whichever size newer card I've tried is the Addonics CF to IDE. They're not cheap - I bought mine for about $25 USD apiece - but when you want something to just work, it's worth the price.
Couple that with an Acard SCSI-IDE adapter, and you've got a CF to SCSI which will work with any size modern CF card. It'll be quick, too, as you can see if you search around 68kmla (I posted some benchmark results somewhere a while ago).
Nice, but external and expensive as heck!