Special slide rule to calculate the carbonation level / CO2 content in ‘volumes’ or grams per litre from measurements of pressure and temperature.  Used in conjunction with a testing device TE01.
 
Achieving good results depends on following the correct operating procedures, and ensuring consistent test conditions to achieve reproducibility.
 
Absolute accuracy is not guaranteed although this method for CO2 determination is reliable and is widely used in the drinks industry. It is recommended to compare results with those from an accredited laboratory from time to time.