Our goal is to redefine how you travel, and the hook-up system is a big part of achieving that goal. Essentially, all backpacks hook up to all roller bags.
The Bastards and The Douchebag fit perfectly with The Huggers, The Carryalls, The Avenue, The Backpack and The Backpack Pro, The CIA and The CIA Pro The Petite and The Base. The smallest backpacks can be hooked onto The Aviator.
The idea behind the Db hook-up system is to take the weight off your shoulders/back and add it to the bags rolling on the ground. The design allows you to hook two hook-up compatible backpacks together, but we don't recommend this as a setup to carry on your back. The design allows this in case you need to hook two backpacks onto one roller bag.
Give us a shout if you would like us to elaborate on your specific product needs.