Ortlieb

I have both the 4.1L and the 1.6L sizes. There isn't much point to the 1.6L since the 4.1L can fold down to almost the same size.

The 4.1L can hold all the tubes and layers for a multi-day ride/brevet.

The sturdy seat rail clamp stops any swaying of the bag.

The clamp doesn't work well with some seats/seat-rails, especially if the seat is pushed all the way forward on the seatpost. It works fine on my Pro Stealth seat.

These panniers were an upgrade from a cheaper REI double sided one that I used for a while. I found my old set wasn't keeping my clothes dry (I primarily use these for commuting) on rainy days and wanted a set I could use not only for commuting but bikepacking down the road. These are everything they say they are and then some. Very simple fool proof system for attaching to all of my bikes (a commuter gravel bike and a fat tire bike). They transfer easily due to the simplicity of the latch system. Also, the latch system is super durable. The material is extremely durable; it's sustained a couple decent wipeouts with minimal damage and is completely waterproof. Not a drop of water gets in. I kayak as well and the design is similar to my kayaking dry bags. The volume of material they hold is a huge upgrade as well. I'm able to fit everything I need for daily commuting in 1 of the bags. Great purchase, simple design and looking forward to years of heavy use out of these.

I looked and looked at cheaper off-brands of panniers to save money but concluded they just aren't worth it. This is one product where a top name brand like Ortlieb is so worth it. Very solid attachment with a lower adjustable hook and the solid clips around the top bar. But still easy to release. Water proof treated cordura nylon is more flexible than their main ones made of drybag material and allows a useful outside pocket. They are some of the larger regular panniers you can buy too. 42 liters for the pair if I remember right. The only downside is it takes a minute to go from fully snugged down empty to opened up wide (unclipping, loosing straps and top draw string closure etc). For everyday I have a simple zipper pannier on one side for my lock and stuff (but those are never fully waterproof) and one of these on the other side for groceries, etc, but for touring I go with both of these on the rack.

I use this seat pack(11L) for 1-2 night tours or long day trips. Works great! I can stuff a full change of street cloths plus a pair of leg warmers with room to spare. Closes up nicely and stays put! Easy to mount. Solid construction. Made with top quality tough materials. Initial price might seem a bit high, but it will last many, many years! BTD shipped immediately with no problems whatsoever!!