We carried some less than attractive seat bags for awhile, they were fine, but we wanted to do something more, so we had these made, and they are great.  Really keep all of your stuff dry, very good zipper that isn't breaking even when the bag is stuffed, they stay very snug to the bike, and have a loop to attach a light.  Best of all they are made in the USA, and they have a 100% lifetime guarantee, They are green and say Campus on them and we like that. 32 cubic inches for the small one, 49 for the big one.

Inertia Pro Wedges are for riders who demand the best. In addition to our standard bomb-proof construction and superior materials, all Pro Wedges have YKK Uretek water repellent zippers to keep water, dust and grime out or your gear. All bags have a side release buckle on the strap for positive attachment no matter how big the drop or long the climb. At the seat post we used One Wrap with molded hook and super soft loop to prevent snagging your shorts. The bidirectional hook and loop can be wrapped around the seat post with the tail to the right or left as you prefer for a perfect fit. The reflective strips on all bags have added bar tacks for more stability when attaching a flasher. All bags also have two interior pockets one on the side for tire levers, etc., and on the back flap for cash, ID and keys.