Everything I buy a 4 pk of the pods for 25.00 (they are expensive) at least 2 of the 4 are not usable. For example, one worked for about 7 puffs and then would not smoke at all afterwards while still mostly full. Another one in the pk kept having a bubbly sound while using and while I flicked the cartridge several times to remove the air, no matter what I did, it bubbled, and then the nicotine would spill off in my mouth. I will never buy it again, cause like I said, they are expensive, and obviously there are no quality control inspections on the cartridges they are selling and I end up ripped off onthe purchase