A truly massive messenger bag, the XL boasts the sort of capacity normally found in backpacking sacks.
If you're lugging massive loads through city streets, then you'll appreciate the rugged waterproof construction and 60 litres of space, with dimensions big enough to take an A2 folder and a couple of boxes of photocopier paper. Yes, it's that big!
Longer items can be strapped externally, and the hook and loop/buckle-down flap is super-secure but gives easy access for speedy deliveries. Add a stable, sturdy base and you've got yourself the ultimate courier's luggage.