This is Surly’s 29 x 3-inch Presta valve tube. It fits their Knard tires and is made of butyl rubber.
Huge tires necessitate huge tubes, so Surly presents the Toob. Its available in 1mm or 1.3mm wall thickness and is made to fit 3- to 4-inch tires. Its equipped with a removable valve core in case you want to fill it with sealant.