It looks like SD dropped the non-ATSC 3.0 Connect Quattro and renamed the rest of the antenna tuners to Flex.
They still suck for never making the Prime 6. 
From SD's forum: A natural evolution for the product, FLEX replaces CONNECT.
Basically, the Flex is the Connect, but with a USB port for an external USB drive. Attach a drive, and the Flex becomes a Scribe. (With all the limitations, meaning the drive would be useless to Channels.)
Ah. Gives them a reason to raise the cost of the product too.