It’s unclear to me if the ferrite bead actually does anything, perceptible or significant or otherwise, for the user, especially given that a user typically only is using the USB cable for charging or data transfer and not generally for listening purposes (unless a user connects a player to a computer to listen to music through the computer; and I guess that the cable may be used as a listening transfer cable in some car stereo setups).
USB cables on the market typically don’t seem to come with ferrite beads (I’ve generally only seen them on cables coming with SanDisk audio players, although I may have one other cable, that came with a Canon digital camera, that includes a ferrite bead), either with other audio players, other electronics equipment, or as replacement/additional cables. It’s always been interesting to me that the SanDisk original cables have the bead and, like Tapeworm, I have wondered why SanDisk includes it (nice that it does, if there actually is some performance factor somehow–one would think that there must be a reason for SanDisk’s practice, although, who knows).
From the SanDisk store link, it’s unknown if the USB cable sold separately by SanDisk has a ferrite bead on it–ther’s no information there, including concerning the cable’s length, although the cable is listed as a “replacment”–maybe it’s the same as the original one. An unfortunate killer at the SanDisk store can be the separate delivery charge, as so often is the case in buying small items mail order/through the Internet. (For me, the ship cost almost doubles the total purchase price, to $12.99–alot for a USB cable.)