The SCHWALBE MARATHON Plus Tyre HS 440 Twin Skin Reflex 26x1.75 Wired features SmartGuard, one of the most efficient puncture-protection belts available for bicycle tyres. Solid, 5 mm thick layer of highly flexible special rubber provides permanent protection also in the case of embedded objects. Even thumbtacks are no problem for this tyre. Improved Rolling resistance The patented, 5 mm thick SmartGuard layer, when compared to all generic products, has a significant advantage in rolling resistance. We further extended its lead in the latest version. Also in the SmartGuard, we now use a proportion of recycled rubber from old latex products. "Anti-aging" side wall It now lasts much longer before developing unsightly cracks when subjected to use with too low air pressure.