Thank you for viewing. Please feel free to comment if you have any questions. The Leanweight MSC (Multi-Sport Compressor) can be used year-round with an OMM rucksack for additional storage. It's a compressor for storing everything from a bike helmet to waterproof gear outside of your OMM pack. It has multiple compression points on both sides for even distribution. The stretch mesh allows the compressor to take the shape of the stored items for a secure carry, and the Leanweight also includes two shock cords for side compression. We will ship via simple shipping.