There are five sizes on the list and none of them is the best one. What matters is how much you get through and how annoying it is to change a unit halfway through a busy night.
The 666 g charger is the small one. It fits a bar putting out a handful of drinks an evening, a cafe, or a pastry kitchen working to order on compatible equipment. It stores anywhere and a spare costs you no space.
Two kilograms is where most working places land. A restaurant with desserts, a cafe that never quite stops, a caterer packing for a job. Several brands sit at 2 kg, so what usually decides is the kit you already own.
The 4.33 kg unit is for one specific problem: swapping a smaller charger twice in a service. If that is you, this size is the answer.
The 5 kg and 10 kg tanks are a bigger commitment. They want a compatible regulator and somewhere sensible to keep them, and they only make sense where the volume is high and steady.
Whatever you pick, check it against the current manufacturer instructions for your regulator or siphon. Send us what you have and we will look before you order.