Perfect size for 1 tube, 2 levers and a multi-tool!
Small compact pack just big enough for a multi tool, CO inflater and a couple of other small essentials. If you want to squeeze in a tube as well i would go for the next size up. Easy to attatch and is a secure fit.
I bought one of these as a trial for one bike, and within a day had ordered a second (see other review). I think that's testament enough to how good they are.
Don't be fooled by the word small! Yes it is small, but in mine I've managed to get an inner tube, 3 tyre levers, multi tool and spare batteries. Not a massive amount, and quite tight, but certainly the essentials.