Originally Posted by
lphillips
I use medium Ortlied Office bag and a padded sleeve. It got a really good waterproof test on my way home from Newton, MA today (very heavy rain!) It attaches very securely to my rack and is a cinch to attach. It's a little pricey, but well worth it.
+1 The only difference is that I have the large Ortlieb Office bag. Waterproof and durable.