The bag is very well made and reinforced were needed and easily adjusted to different handlebar / head tube diameters etc. . The main compartment opens at both ends and rolls up in the style of a waterproof dry bag, my bag that was sold in Japan also included the recommended Outdoor Research 10 ltr dry bag in which to store your down sleeping bag / clothes etc. When riding with the bag full it does not affect the handling of the bike and when adjusted firmly with the super tough velco straps and adjustable buckles it it does not move around at all. Pictured below is the right hand side opened and the dry bag which fits neatly inside the main compartment.
With the bag adjusted you can easily alter the height of the main bag on the handle bar and the front bag can also be adjusted at the required angle e.g low or high. I imagine the front bag would be useful for carrying small items such as a wallet, compact camera, snacks etc . I tested it with a 110cm Abus shadow chain lock which is quite heavy and the bag held firmly on my 16km daily commute.