The String-Me-Along includes a clear, interchangeable project exchange bag (I have three) to hold supplies, and a work surface that is the unrolled bag with a velveteen interior. The whole thing rolls up and is secured with a strong elastic strap for travel, and the project exchange bags can unsnap and be exchanged for another project already in the works. It is really cool. I love mine, and it has been living in my purse since I got it.
See Heather's full review here: www.caravanbeads.biz/beadblog/archives/1663
PS Since we started carrying these project bags, the Caravan retail staff have become totally addicted to them. They're great for other crafts in addition to beading: if you're one of those people who likes to have multiple projects going at the same time, the String-Me-Along bags make it easy to stay organized.