Ah, I see some have an " active" extension -like a booster added onto the ends. that's why it has a larger area on one end of the connector.
So the ones with that extra will cost a bit more , but from the info below it's looks like 16' is the max without the booster.


some info on it
[One of the biggest obstacles encountered in planning a wire run is the signal limitation of USB devices. With a maximum guaranteed length of 16 feet, very few USB runs are successful without the use of ACTIVE extension cables. These are M/F extension cables which feature a booster-box on the end, and when strung together, can achieve a new maximum of 80 feet. Easily extend your USB 2.0 cable past 5 Meters by daisy chaining up to five of our premium USB 2.0 active extensions. These USB 2.0 compliant cables support data transfer rates up to 480Mbps and are fully backward compatible with both low and high-speed USB v1.1 devices. ]
more here
http://www.tigerdirect.com/applicati...9301&CatId=444

here's as similar one on ebay-
http://cgi.ebay.com/16-FT-USB-2-0-Ex...d=p3286.c0.m14