This is a great value for 8 gram cartridges! These are made to fit the cream whipper we sell. Each cartridge holds enough gas to whip up to a 1/2 liter of whipped cream. The cartridges also fit the Tap-a-Draft Tap and can be used to create a sweet dense foam on beer if used to dispense homebrew instead of using CO2 cartridges. They will not carbonate a beverage, so the brew should be carbonated with CO2 cartridges or by priming with bottling sugar first. Contains nitrous gas (N2O), not nitrogen, so may not be appropriate for beer recipes requiring pure nitrogen. The 8 gram cartridges are not threaded. Packaging may vary from photo, but the gas cartridges will always look just like they do in the photo. Constructed of steel, gas cartridges can be recycled where scrap metal is accepted for recycling. **NOTE: We can only ship these cartridges by UPS Ground. The US Postal Service considers them a hazardous material.