Previous experience was with Jandd and Rhode Gear. Have a Jandd 6-Pack Expandable I bought back in the 90's and is still in use today. Quality is high, especially since it lasted over 25 years and is starting to list a bit to one side.
The Stowaway Bag serves a niche in the area that is not being used on the trike. http://shop.terratrike.com/product-p/tt600345.htm
Had noticed this unused area back in October 21st, 2016, shortly after I bought the 2016 Rover. See, Jandd has frame and other bags that fill in areas, and this one seemed obvious.
- In the summer of 2017 TerraTrike & Chonk announced the Stowaway Bag
Had noticed the original photos of the Stowaway Bag looks to have a more rounded back end than the frontal section.
Then seen the latest ones Chonk posted the look more flat front to back now. - which is the way it was received today; more flat all across. Have not had the time to put on the Rover yet. Will get to that as time comes.
As you can see, the Expedition Pannier can also be used with the Stowaway Bag in place. Is rumored there could be an electronic-assisted kit for the Rover, in which the batteries could be attached to either side or both as well as extra TerraTrike Panniers.
The idea of the packs, mounted on the Low Rider Rack, is to keep weight down low on the trike. This allows the advantage in having a lower center of gravity whilst also utilizing an area that would otherwise be unused. The interior is of a soft material in which the velcro baffles adhere to.
These sections can be removed and placed per the user's desire, and the center area does go through to the other side with the baffles removed.
However, rigidity is lost when the baffles are removed from the center, and the center could collapse downward. Still, this is behind the seat and should not matter.
Top Front - 2 Straps on either side, could be for a universal fit for all the trikes.
Bottom Back - Four velcro tabs to hold the bag securely down on the Low Rider Rack. (Mounting hardware sold separately.) http://shop.terratrike.com/product-p/tt600361.htm
Low Rider Rack on a Rover