Schwalbe SV18 Extra Light Tube (700 x 28-42, 40mm Valve)
Schwalbe SV18 Extra Light Tubes are made from 20% recycled rubber, so not only are they low in weight, they're lower in their carbon footprint. All valves are nickel plated and threaded and valve inserts are replaceable. Perfect for wider trekking tyres. Less likely to leak, and more reliable.