I used a C02 cartridge Friday for the first time. It worked well. I now carry one of these and a tube everywhere I go. I also have a new tube and pump in my office at work and full tire repair set up at home. I am very fortunate to be allowed to keep my bike in my office and am allowed to make tire repairs there. With this kind of support, I am still very hopeful that the Gatorskins will reduce the number of flats I've been having.