Lone Peak pannier. Transforms into a backpack, with the rack attachments folding up into the bottom to hide away. Pannier is approximately 16" long, 9 " wide, 7" deep (a little small, although the top expands up to 19"). Top rack clasp can be closed to lock around the bike rack. In good condition, just a little dusty.  $25.  Pick up on weekends in Hyde Park or during the week in the Loop.