Material: nylon Mount: seatpost Closure: zipper Dimensions: 5.25 x 2.125 x 3.5 in Recommended Use: cycling Arundel's Dual Seatbag is pretty straightforward -it carries two tubes (thus, 'double'), two CO2 cartridges, an inflator, and tire levers -everything you need to get your bike back up and rolling in the event of a flat. Like everything Arundel makes, though, the devil's in the details. There's a single strap the secures the bag around your saddle rails, and it holds quite firmly, negating the need for the all-too-common seatpost strap that inevitably wears through your bib shorts. In addition, Arundel reinforced the point of the bag where it contacts your seatpost bolts with a small leather patch, so your post won't wear holes in the bag. The zipper is large, and has an easy-to-grab pull, a little thing we appreciate when wearing full gloves.