From the Pitchfork Article:
The 512 MB USB 2.0 flash drives will come in two editions of 3,333 apiece. Half of them will creepily look like Meg, and the other half will creepily look like Jack (both are pictured).
The drives are available separately or as a pair, and all of them will come pre-loaded with Icky Thump in Apple Lossless format. They will ship the week of June 19, which is, not coincidentally, the album's U.S. release date (June 18 in the UK).