I have the tail pack and the tank bag and I really like them both! I do wish the tank bag had small zippered pouches on each side, like the tail pack, for small things which are handy to have easily to hand, such as change for parking meters or tolls, ear plugs etc.. Les is easy to work with and he will customize the bags for you within reason. I'm not sure how water proof the bag material is, but the zippers are all covered with flaps and that's where most leaks occur in luggage. Rain covers are available for all his bags. It's a really well made product. I like the easy remove-ability of the lock on tank bag when I stop to get gas and/or to transport my electrical gadgets in when I leave the bike parked somewhere where I can't watch it.