I can not read this Tsjech language either, but by looking at the numbers I can see what is meant.
If that does not work for you, please have a look at the

Dutch
http://mvvs.nl/

German
http://www.mvvs.net/

Canadian
http://www.mvvs-canada.com/moreinfo.php?pid=3

Distributer.

The number of the exhaust and rpm is mentioned.
Look in the list of exhausts to mach the number given in de rpm list to the number of the exhaust.
The 3270 is a in-cowl muffler if this suits you better.

There is no BS or hocuspocus.