These bags are of very good quality and very functional. Easy to adjust to your racks and the ability to move foward or backward when mounting. I've used them on a couple of bike camping trips with no issues what so ever.
Better yet, Western Bike Works always has great sales and excellent customer service.
After 3 years of daily use the pannier is only suitable for use in dry weather (holes forming at corners and folds). Not a bad run, I bought a new set to use in the rain.
Perfectly watertight for well more than my needs, and the Medium has plenty of space for tube, multi tool, tire levers, patch kit, a blood sugar test kit and glucose tablets for this diabetic. If you arent carrying the diabetes stuff, a packable jacket can be crammed in there.