B&W's Foldon Bag, designed to fit Brompton folding bikes. It's made of tough nylon fabric for travel on train, bus or car with heavy-duty zippers and straps. Folds into a very small package for commuting. Might also fit other folding bikes like the Frog. Perfectly fitting bag for B&W's Foldon Box.
How to Load your Brompton into the case
NYCewheels shows how to use the hard case
UK flavored Instructions for loading up you Bike