Carboxy therapy pen for gas inflations

[Apollo061]

I recently bought this carboxy pen from Ali express under the recommendation of Tx_Intact guy from this site. Since it only works with CO2 cartridges because of the threading that what I’ll be using. Any specific brand or type of gas should I use? I assume that any “food grade” co2 you can find at the grocery store or on Amazon is safe. I’m real excited to use the inflater, I might buy infusion sets so I can have a bit of a hose attached rather than a stationary needle attached directly to the device. Anyone have experience with n2o or co2 and can tell the difference?