After having to rescue the bike hermit twice due to CO2 pump failures we threw them in the trash. I have also been riding with a friend and had to rescue her with my frame pump because her CO2 pump failed. We have had the best luck with Zefal but also like the Topeak Master Blaster (smaller) and it has a handle for better pumping action. I know alot of people love the CO2 but nothing worse than being 50 miles from nowhere and having the cartridge fail