This is a crucial question. Rotass chargers are typically standard 8g threaded (or "piercing") cartridges. Most modern SodaStream machines, however, use a proprietary, quick-connect CO2 cylinder that is larger and not physically compatible with these standard chargers.
Important Note: You cannot directly use a standard 8g Rotass charger in a SodaStream machine designed for its own cylinders without a specific, often third-party, adapter. The use of such adapters may void your machine's warranty, so it's essential to check your device's manual and local regulations before considering this route.