We teamed up with our pal James at Beard Bags to create these awesome seat bags right here in our South Minneapolis neighborhood. They are built with Made in the USA waxed canvas from Fairfield textile and will age beautifully with use. The Adventure size is designed to fit a 29'er size spare tube, multi tool, tire levers, spoke wrench, chain tool, and a spare derailleur hanger. Size: 4 x 7 x 2" The Gravel Size is designed to fit a 700 x 32c size spare tube, multi tool, tire levers, spoke wrench, chain tool, and a spare derailleur hanger. Size: 3 x 6 x 2" Use our included strap our your own preferred Voile or toe strap to quickly attach to your saddle rails. There's also an optional loop on the end of the Adventure size if you'd also like to attach it to the seatpost.