I purchased this seat bag to replace a Blackburn bag I've used for years. I shopped other brands but decided on buying a Blackburn bag again. I went with the large size, its a bit bigger than I need but still not too large. The water resistant material, practical inner design and great zipper all are nice features. This bag also secures tightly - no worries of it becoming loose. In use for a couple months, no complaints. Great looking bag as well.
Size Med , but I ride tubeless tires, so no inner-tubes in my seatbag, so I could get by with a Small. Also, no tire irons or patch kit.
I have room for CO2 cart & chuck, 1st Aid Kit, micro Leatherman, Visine bottle of anti-bacterial soap, Topeak micro tool, chain Quick-Link, GU, CC-sized gate key, and 3,000mAh USB charger, although that might have to stay behind if I were using the small size. Lately I've been carrying a medicine bottle filled with GatorAid laid sideways across the top in back.
Love the reflective sides, they show up well at night, and in photographs using flash. Like the wrap-around main strap, and dust/waterproof zipper.
CAVEAT: The Velcro loop around the seatpost has a rough coating on it that will chew up the legs of your shorts. Replace it ASAP with something softer and non-abrasive. I remember distinctly writing Blackburn a nasty-gram 10yrs ago about this same issue. I used a Velcro strap with the soft, fuzzy side out. Works great.
The large is a bit of a weird size. It is just a bit too small to fit a jacket, some tools, and a couple of bars. I would buy something 20% larger.
Quality is high, Zipper quality is high. It definitely keeps the contents dry during some moderate rain.
Needed a larger saddle bag to carry my new larger smartphone. It has two separate compartments separated by a soft liner to protect the phone from being scratched from tubeCO2 cartridge. I would have preferred Topeak type clips instead of a large velcro strap.
With this pandemic going on and needing a mask i needed more room for carrying a mask, didn't want to put it in jersey pocket. It also has given me room for small bottles of sunscreen, hand sanitizer and my wallet. Great buy.
Its a good bag. Hold emergency repair kit and a multi tool. Only issue I have is color fading away within couple of month. My bike stays in garage, and only when I ride its in the sun