I use panniers for shopping. Unfortunately, my Rudy Project panniers were discontinued long ago, may even have been prototypes, and I am having trouble finding suitable replacements, as they are nearing end of life, with nylon rips.

They have stiff inner boards to keep them from flopping into the back wheel (essential!), and each can hold a box of cat litter, 30x29x10.5cm. They also simply drop right over a Pletscher mousetrap or Blackburn MTN rack, the ultimate in easy on / easy off.

I have found some $90 rollup canvas units that appear to be about the right size, but I about stiffness.

I am wide open to suggestions and advice.