Race Tech shock shaft bushing driver set sold by Schmidty Racing Suspensions is used to install shock shaft bushings into seal heads. This set comes with 12.5mm, 14mm, 16mm, and 18mm drivers.
If you are rebuilding shocks on a regular basis, its way cheaper to replace the bushings and seals vs buying a complete seal head. Plus, with some rare or older bikes, you may not be able to find a complete seal head. This has all the common sizes, no more hunting for the socket that's "close enough"