Very high quality Mountain Bike inner-tubes prefilled with Joe's Super Sealant- the world's leading tire sealant, prevents flats by instantly sealing punctures in the tread area of the tire up to 3mm. 220 gram inner-tubes prefilled with 120 grams Joe's Super Sealant (total 340 grams for 26" tube). Tips: * If you get a puncture, always SPIN the wheel to distribute the sealant. * If spinning does not work, find the hole in turn the wheel so the hole will face the ground. * Add more air if necessary. * Enjoy the rest of your ride!