If your not sure what these are all about do a search on the forum for flux plates.
Essentially these plates replace the oem ones which are have a profile/angle which is progressive to allow for riders of all different weights.
These replacement plates have a different angle / profile so they make the linkage linear not progressive, which in doing so reduces the kick in the spine over higher bumps.
Simple change which makes a big difference on the road, and a good bang for the buck particularly if you’ve still got the standard shock fitted.
Picture in link https://imgur.com/a/THYULhY
Looking for £20