I am having these installed on my F250 next week in place of airbags or Timbrens.
https://www.etrailer.com/Vehicle-Sus.../RAS4611.html?
gclid=EAIaIQobChMIjv-C5rWr2gIVWDZpCh1wowcFEAAYASAAEgJywvD_BwE
Design is to enhance the trucks suspension as engineered through the leaf spring system.
The jury is still out on performance.
RMc