The MTX Trunkbag EXP is the definision of a simple bag to use.
It's very simple to put it on the Topeak rack. You just need to slide on the rails on it's ok.
It weighs 1160 grams and have a capacity of 22,6 liters.
The two laterals pockets can be store simply on the sides if the bag.
The principal pocket is a litlle bit rigid and have a removable separator depending what you want to store in it.
To finish, you have a small pocket on the extremity of the bag to put a flask or other objects.