A warning on REI:
I bought Ortlieb backrollers from them last June when they were on sale for the same 25% off. They have a "guarantee" on their site, so when one of the four clips worked it's way loose and I lost the mounting screw somewhere on the side of the road in NH, I wasn't concerned. When I actually called to have them replaced/repaired, Customer Service gave me Ortlieb's 800 number and said "Good luck."
The REI Guarantee sucks. I wish Zappos.com had more bike gear, their customer service is damn near legendary and I buy everything- EVERYTHING -else there. Never had a problem.
Luckily, Ortlieb mailed me out replacement parts, no questions asked.