Extremely airtight! The Butyl rubber compound prevents pressure loss and fewer occassions to inflate. Extremely reliable! Quality control for safer cycling: Each tube is checked twice at the factory to ensure safer cycling. Having the correct pressure means fewer punctures and reduced rolling resistance
PJFound Schwalbe inner tubes to be decent quality, and particularly like that the valves are metal all the way through the frame
Sir PeddlesworthHaven't used them yet but they are the same ones which came with my bike so I got some more just in case. If my marathon plus tyres can't save me from a puncture at the road side these will step in. £4 can't go wrong.