The Blackburn Outpost Elite is designed to be compatible with both dropper and standard seat posts, offering generous storage space and stability to prevent swaying even on rough terrain. The Seat Pack is a two-part system: Part 1 is a T6061 aluminum rack that attaches to the saddle and can be used with both standard and dropper seat posts. Part 2 is a removable and waterproof bag that features a vent valve, allowing for quick compression of the bag. The rack remains on the bike while the bag can be easily removed, folded, or repacked – all in no time, so you can get back on the bike as soon as possible.