I bought a new bike and wanted x-tra bottle holding capacity so I installed a two bottle unit behind the saddle. This storage bottle fits nicely behind the saddle. I have the 600 and there is TONS of room in it for two tubes, a few CO2 bottles, some tools, gel, inflator, tire levers, etc.
I find this type of storage bottle useful for shorter rides. I have the mid sized bottle in which I carry a hand pump, tire levers, tubeless plug tool, a multitool, TPU inner tube, patches, and a quick link.
It's out of the way, secure and easy to access. No weird issues with the cap unscrewing itself so all in all, a handy thing to have for the intended short rides. Any color you want as long as it's grey.
My only nit pick, the bottle material is thin. I wouldn't over pack it as I fear It might tear.
This is a good product to store tubes, CO cartridges, etc. if you don't want to use a saddle bag and if you have a spare water bottle cage to put it in. I got the largest size offered and I have a 32mm tube, 2 CO cartridges plus adaptor and multipurpose tool and it was a tight fit. If you want to ride with a saddlebag but use this as a back for snacks, keys, etc then you can probably go with a smaller size. It's sturdier than a saddlebag but the biggest considerations to give when getting this will be what are you carrying in it and do you have a second (or third) bottle cage to carry it in. I use this on my gravel bike and have two cages, if I want to ride with a second bottle then I'll either need to add another cage or revert back to a saddle bag for the ride.
I wanted storage for tubes and tools but I have behind saddle bottle holders. This holds plenty of stuff and is 100% waterproof.
I like to store my rain coat in Elite Byasi. A regular water bottle does in and out instead of straight down which makes this more convienent. It also is lighter.
This tool storage bottle is big enough to hold all my tools for multi-day rides. Lid is secure and stays tight even after riding off road trails.
This 'bottle' makes a perfect container for a take-along tool kit. It fits perfectly and inconspicuously in the bottle niche on the rear of my Topeak rack-trunk bag.
This fits a spare tube, two CO2 cartridges with chuck, two tire levers. What you need. It is not too big, fits great in bottle cage.
