This is Surly’s 29 x 3-inch Presta valve tube. It fits their Knard tires and is made of butyl rubber.

Surly Inner Tube to fit a wide range of plus-size and fat bike tires. - Labeled Size: 26 x 3.0 - 4.8 - Weight: 310 g - Valve Core: Removable - Shaft Type: Threaded - ISO Width (mm): 76mm–100mm - Tube Compound: Butyl - ISO Diameter: 559 / 26-inch MTN - Valve: Presta Short 32-40mm