Google Customer Reviews 
Racktop bags are the most convenient bag you will ever put on your bike rack! For things you need ready access to, you can’t go past a trunk bag.
Racktop bags come in loosely 2 categories. There are touring style bags that integrate with panniers on your rear rack. And then there are trunk bags that are a standalone bag.
Touring style bags like the Ortlieb Rack-Pack are intended to be slung over your panniers with clips to secure the 3 together. Simply an excellent idea for touring, these bags are also waterproof. And you will never need to dig in your panniers for a particular item.
The trunk bag option will be a game changer for you if you are a commuter. A simple roll-top or zip closure bag that is easy to access, and no need for panniers. We love this option if you aren’t sure if you need all the space of a pannier.
