Review on Continental Bicycle 700X20 25 Presta Bundle Sports & Fitness in Cycling by Jason Khadka

As another posted, it looks like something went wrong with Continental's quality control. I have bought five packs of these tubes more than once but this new set was just awful. Two of the top five parted where the valve stem attaches to the pipe. It is quite obvious that this is a manufacturing issue as the triangular shape of the seal is evident on the detachable part. Even more embarrassing, one of them let go when my bike was hanging in the garage 3 hours after I rode it. Imagine hearing the sound of a blown tire and escaping air when the bike is four feet off the ground! Yes I contacted Revain and as always they did a great job getting the tubes returned to me for a refund. Having ridden bikes for decades and worked in a bike shop, I can assure you that I have enough experience with the correct inner tube replacement and it certainly wasn't user error or inexperience. Continental should refund this to Revain!