How to read Material core Code Eg. 3W800

Hi! I am looking for a magnetic core for my Common mode choke. I am trying to understand its datasheet so I can also simulate if the core material will fit my requirements. I have check at different online stores and most of the available cores are from Wurth Electronics with little details available at their datasheet. And at its material core it gives the code number of 3W800, can you please help me how to understand its code..

below is the link for sample datasheet..

http://katalog.we-online.com/pbs/dat.../742701111.pdf