What are cream chargers?

These are whipped-cream chargers, steel cylinders filled with nitrous oxide, used as a whipping agent in whipped cream dispensers.

 

What are cream chargers used for?

A whipped cream charger is a steel cylinder or cartridge filled with nitrous oxide (N2O) and used in a whipped cream dispenser as a whipping agent. 

Nitrous oxide canisters have a foil covering on the narrow end that must be broken to release the gas.