I worked out the failure rate and out of a box of 24 usually 3 were duds (didn't properly puncture due to poor seals). When you work out the numbers and compare to the pricier products (Whip It and ISI) I find that you pay the same per working cartridge. This means that per order you are getting less viable cartridges which means more frustration and interruption of flow. Six of one, half of one less a bakers dozen of the other. 3.5 stars. I recommend but with the caveats noted above.