The product range of tubes for mountainbike tires is quite extensive. You'll find normal tubes as well as lightweight and ultra-lightweight tubes.

unitube	dimension	D40	A40	S42	S52	ETRTO	versions
MTB 26	47/62 - 559	x	x	x	x	47, 50, 54, 57, 62 - 559	26 x 1,75, 1,9 - 2,0 - 2,1
							26 x 2,125 - 2,3 - 2,5
MTB 26 Light	47/62 - 559			x [126 g]		47, 50, 54, 57, 62 - 559	26 x 1,75, 1,9 - 2,0 - 2,1
							26 x 2,125 - 2,3 - 2,5
MTB 26 Supersonic	47/54 - 559			x [100 g]		47, 50, 54 - 559	26 x 1,75, 1,9 - 2,0 - 2,1

The advantages of the Continental Unitube system

• Multi-size tubes allow greater compatibility with more tire sizes, and fewer tubes.
• Unitubes are available in both Schrader and Presta valve tubes. Presta valves are available in a variety of lengths.
• All tubes are seamless and mold-cured (vulcanized) to ensure uniform roundness and improved reliability at the valve stem.
• Each and every tube passes a stringent 100% quality control inspection