Tubis are very similar in construction to the Dual but longer and skinnier. It will hold a tubular tire or regular tubes, plus extra supplies. 35 cubic in.
From another website:
"Enter the Tubi. A Cordura bag designed to fit that tire, it has just enough room for a sew-up, a CO2 cartridge or two and an inflator. There are two small side pockets for loose tools and cash. A single strap in the middle of the bag goes around your seat rails and then the bag. There's a genuine leather tab on the back so the seatpost won't wear through the bag.
Expensive tubulars usually fit better than cheapies as the casings are typically thinner and more flexible, so they fold smaller. Start by removing the excess air from the tire. Then, you can start folding at the valve stem with the tire around four fingers of your hand and go from there, wrapping tightly the whole way. The Arundel Tubi can also be used for people who ride clinchers and either like carrying a folding tire in their bag or just like having extra tubes and tools along for the ride.
The Tubi is a great option, too, if you ride a mountain bike and you aren't keen on wearing a pack. You can fit a couple of fat MTB tubes, some CO2, and a multitool with space to spare. Be well-prepared sans back sweat!
The Arundel Tubi has 28 cubic inches of internal volume. The dimensions are 7"x4"x1". Claimed weight is 82g."