WHAT DOES 13B ROTARY ENGINE FOR SALE MEAN?

my son require an engine for his vehicle so we took a chance ,and all I am able to say is thus far so superior .it had been shipped in a very well timed manner and after we acquired it in and hooked up and everything that that goes with that again set up it run like a new just one .as of at the moment I'd definantly buy again And that i will likely