One of the issues in modern chemicals, pharma, and food industries is to deliver safe and reliable products. The stability and performance of many of such products depend on constituent particle dispersion state. Usual analytical techniques often use dilution and other dispersion preparations methods to evaluate particle size, size distribution, and other parameters. What if we could measure that mean particle size in as-is products such as paint, beverages, vaccines, or oils. In fact, ISO has just released an internationally accepted method for measuring mean particle size in very dense dispersion samples. This is ISO TS 21357. It is the result of a very hard international work and collaboration strongly supported by national metrology experts from UK, France, Germany, Poland, Japan, USA, Canada, Mexico, Russia, China, the European Commission, and many others. This presentation will describe the advantages of the SMLS method, the ISO documentation and give an outlook where this leads our industrial partners and metrology community.