SkyWatcher

Telescope ModelOTA Thread FocuserAdapter 
Equinox 66M73x1FTF2025BCRA20-731 
80/100/120 ED and Evostar 80/100/120
Non threaded 3.804″FTF2025BCRA20-292OR
  FTF2015BCR-RPA20-3003-8OR
  FTF3035B-AA30-1903-104 
Esprit 80M109x1.5FTF3015B-AA30-1903-28 
Espirit 100M128x1FTF3015B-AA30-1903-102 
Esprit 120/150M147x1.5FTF3035B-AA30-1903-103OR
  FTF3545B-AA35-503-103 
SkyWatcher Newtonians / Quattro SeriesNon Threaded  FTF2025BCRA20-240 or A20-241 
SkyWatcher Equinox RefractorsM84x1FTF2535HDA25-2003-20 

The 2.5″, 3.0″ and 3.5″ Feather Touch focusers will need an end cap and the most popular end cap for the 2.5″ focuser is the EC25-2005-1 which is a 2″ compression ring end cap.

For the 3.0″ and 3.5″ Feather Touch focusers for the Esprit Telescopes, the most popular end caps are the M65x1 threaded end caps (EC30-1905-65 and EC35-505-65).

For the SkyWatcher Newtonians, which adapter needed will depend on which stock base that is on the telescopes:

A20-240 Or A20-241