SpinSkins Duro are the liner preferred by commuters and recreational cyclists looking for an economical way to prevent bike flats. Just install them in between the tire and tube to virtually eliminate punctures. SpinSkins Duro can withstand up to 3.8 pounds-force from a 0.05-inch diameter needle. SpinSkins provide more puncture protection than other brands while also being significantly thinner. The Duro liner is only .022 inches thick.