![Schwalbe Inner Tube SV21 - 27.5 x 1.50 - 2.40" (650B) Presta Tube - 40mm](http://senacrecycles.co.uk/cdn/shop/products/p5c7029b4a64bb0.24356723_d327a309-b9e2-4ab2-a691-96c8a2121229.jpg?v=1705159592&width=1445)
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