Review on Continental Bicycle Tubes Race 28 700x20-25 S42 Presta Valve 42mm Bike Tube Super Value Bundle - Pack of 5 Conti Tubes & 2 Conti Tire Levers for Optimal Performance by Matthew Riley

I haven't used Continental tubes for a long time and now I know why. The tubes are of poor quality. During installation, the valve inserts were unscrewed several times when the pump was removed. I think it's good that it comes in a pack of 5 because you can only use 1 or 2 that can hold air. I had 3 popups in a row after the installation was complete. I lowered the recommended pressure and used 80psi instead of the nominal 100-120psi. I thoroughly cleaned the rim and inspected for sharp edges, cracks or imperfections in the rim tape and didn't use any tools that could puncture the tubes and still popped out three of them before I could even ride the bike. I opened the fourth pipe on a short tour of the area with my wife. I threw away the fifth. I bought a brand new kit from a local store and haven't had any issues since. Avoid disappointment, buy something else.