Question about a M/F USB extension
 

I've got a headset attacked to my work computer. I'd like to add an extension so I can reach a longer distance from my desk while on a call.

I vagkuely remember that USB extensions won't work beyond a certain length but that may have been in the USB1 days. I found 6 and 10' extensions but then I found a 25' with a repeater.

http://forums.pelicanparts.com/uploa...1590610161.jpg
CableVantage 25 FT USB extension Cord Active USB 2.0 Extender / Repeater / Extension Cable High-Speed 480Mbps USB 2.0 Type A Male to A Female Extension Cable w/ Active Repeater (25 FT)

Is there something to this "repeater" or is it just marketing a cool collar?

I would think that it would have to be powered if it was a repeater.

That's what I thought but I don't see any power attachment. I suspect this is cool collar science here.
So what is the max length unpowered I should look for?

But, uh, USB bus includes power.

Back in the day, I found a USB GPS was pretty iffy on a 12ft extension cable. And that's serial @ 19k2 - hardly a bandwidth hogger...