A packing cube that becomes a daypack and a Western Flyer with two straps instead of one:

Convertible Packing Cube/Backpack

Tom writes:
“I designed the Convertible Packing Cube/Backpack as a result of
customer  requests from our Forums, in fact, I think it’s the first product we’ve made that was 100% inspired by customer
feedback. Many of the details, of course, reflect my design experience, and my sewing crew helped to refine some of the subtleties of the construction. Overall, it was truly a group effort.”

The Convertible Packing Cube/Backpack is a Packing Cube that can be used with our Aeronaut or Western Flyer carry-on travel bags to organize and keep your clothing neat and separated from the other items in the bag. Once you reach your destination, you can remove the contents of the Packing Cube and right-side it out, transforming it into a backpack with two compartments, an “o-ring” for attaching a Guardian Light, Key Strap, or Organizer Pouches, and webbing backpack straps that are surprisingly comfortable for lighter loads.
It’s a great, dual-function bag for those who travel light and need what they take with them to be lightweight and multi-tasking. Plus, the Convertible Packing Cube/Backpack gives you the option of bringing home more than you took with you (gifts, souvenirs, etc.) — use it as an additional carry-on bag on your return flight.

The Convertible Packing Cube/Backpack ($35) is available for pre-order now and ships by early September. Pre-order here:

See also:
Convertible Packing Cube/Shoulder Bag