Has your Mk2 Aqualisa Aquastream mixer shower been underperforming in recent months? Is the temperature fluctuating or is it feeling underpowered? If this sounds familiar then you may need to replace the thermostatic cartridge inside it. These cartridges can alleviate any fluctuations in water temperature, bringing your shower back to its former glory. Suitable for use on a gravity system only Compatible with the Aqualisa Aquastream Mk2 only Replacement thermostatic cartridge