What are Zertz inserts on a Specialized Vita?

[laura*]

So Zertz is something rubbery? This would be my first bike without any suspension so I am willing to give it a go.

My impression is that the Zertz are there to reduce high frequency vibrations - i.e. stuff you'd perceive as buzzing.

They are not an alternate to suspension components. They won't do anything to smooth out a bumpy road.