Harbor Seat Case Dark Brown. A bike lovers essential, the Harbor Seat Case is a must have! Made using a TPU membrane and nylon fabric, welded seams, and locking waterproof zippers, this case is 100% waterproof in both fabric and construction. Easily attach the case to the back of your seat post with the hook and loop strip and strap the top to the bottom of your seat. Stores all of your small items inside while keeping them d