The frame slides into the slip panel on the back of the bag, and secures onto the Brompton block. This enables the bags to be attached to the bicycle as well as having the option to wear on your back. If you want to wear the bag on your back during a trip out and about you can simply put the frame into the bag or leave it attached to the block.
See this blog post as reference to see how it works <<HERE>>
Included in this price is the frame only. Please purchase the bag separately <<HERE>>