engine components

Dear all,

A question for you gents..another one proving my lack of mechanical skill n knowledge.
With the air filter being on the right side of the engine, what is the smaller part on the left side? It's not even listed in manual on schematic...

Many thanks in advance.

That's the pair valve Marcin. Page 161 in the manual section 5-27

Thank you kindly.
I shall read up on it.