Brooks Challenge Saddle Bag

What we have here is a nice leather bag with a pretty clever design.  What follows is Brooks' unnecessarily wordy description of the darn thing. For best results read it to yourself in a British accent! 

"The first Challenge was designed and patented in 1896.  This tool bag is for fitment to the rear of a saddle bearing bag loops. It features buckles that whilst fastening the bag to the saddle, are located within the hold itself, thus ensuring greater levels of security and the strap that secures the unit encircles the tools it carries, to prevent them from rattling during transit.