The standard size whipped cream can (usually called a cream charger bulb) contains about 8 grams of Nitrous Oxide (N2O). These 8 gram cream charger bulbs are a standard size across brands and fit with different brand’s whipped cream dispensers.
However, the net weight of nitrous oxide gas contained inside an 8 gram whipped cream charger can vary from 7.8 grams such is the case with whip it, Ezywhip Pro, MOSA and Bestwhip cream chargers (these three MOSA, BestWhip and Ezywhip Pro are all manufactured in the same factory), and to 8.2 grams such as the Supremewhip cream chargers.
Companies, such as Supremewhip, that have greater volumes of nitrous oxide gas in their cream charger bulbs promote this in their marketing as providing better value to the customer because they get more in each bulb.
However, there is a limit on how much gas can be put inside a cream charger/bulb. With increased gas weight in a bulb there is also increased pressure and if bulbs contain too much pressure it can risk that the foil or seal (the part that is broken to let the gas into the whipped cream dispenser) will break prematurely and the associated danger of that.