I ended up getting a Thule shield large size. They had just gotten them in when I was there picking up the bike and I really like it. Has a small handle that attaches with wires to two rotating clips so when you pull up on the handle they rotate and unlock. A magnet hold the bottom stationary and out away from the frame or wheel. Completely waterproof with a roll up top, shoulder strap and handle. Seems to work really well.It turns out that Amazon will send you a racktime pannier snap it system adapter. The beauty of the adapter is that you can remount almost any rear trunk bag you might have and the trunk will pop on and off to the trunk racket with much ease and use. It is a godsend when you are popping the trunk bag off and on again on a regular basis. It is simple to install the system adapter onto a trunk rack. Check it out on Amazon and by the way, I had to purchase the adaptor out of state some time go.