I am not sure about this, but I think all of IROs hubs are flip flops. Further, they may also all be fixed-fixed flip flops. Maybe. A freewheel will spin onto a fixed side of a hub, but you can't get a lockring onto the freewheel side of a flip flop.

So either the fixed or the singlespeed SHOULD have a fixed-fixed flip-flop hub. Check with IRO though. I think the only difference between the two bikes is the singlespeed comes with a freewheel attached and front and rear brakes; the fixed comes with a cog w/ lockring and the option of getting a front brake installed.

The handlebars in my pictures aren't the stock IRO bars, but only because I already had these bars. The white tape was something I had to get on my own and I wouldn't recommend white tape to anyone. Both sets of bars I have received from them have been bare bars that included black cork grip tape, which I would recommend over some the Fizik stuff that I was using.

Feel free to send me a PM if you want to ask anything else.