Originally Posted by
Miradaman
I was wondering what those weird rubber inserts were. Looks like they're in the seat post too.
Yup. In later years, the teens, Zertz inserts were on the seatstays and the seatpost had this goofy Adam's apple shape to it to help reduce vibration.
Then suddenly, Zertz disappeared because Specialized moved on to other ways to claim compliance and vibration reduction. Based on internet comments, Zertz had long run its course as a marketing tool.
To be clear, there is no harm in having them. It's not like they slow you down.