William Optics
| Telescope Model | OTA Thread | Focuser | Adapter |
| Zenithstar 66 | M73x1 | FTF2025BCR | A20-731 |
| GT81, Megrez 80 & 90MM, Zenithstar 80 | M90x1 | FTF2025BCR | A20-271 |
| FTF2015BCR-RP | A20-3003-1 | ||
| FTF2535HD | A25-2003-14 | ||
| (NEW) GT-81 female thread | M86x1 | FTF2535HD | A25-2003-86 |
| WO 72mm | M87x1 | FTF2025BCR | A20-273 |
| Older Megrez 90 | M76X1 | FTF2025BCR | A20-226 |
| FLT98 Carbon Fiber w/red non-removable ring | M77.5×1 | FTF2535HD | A25-2003-3 |
| FLT98 Carbon Fiber w/red removable ring | M102x1 | FTF3035B-A | A30-1903-22 |
| Megrez 102ED | M102x1 | FTF3035B-A | A30-1903-22 |
| FLT98 w/gold ring | M104.75X1 | FTF3035B-A | A30-1903-2 |
| GT102 | M104.75X1 | FTF3035B-A | A30-1903-2 |
| Zenithstar 105 & 110mm | M114x1 | FTF3035B-A | A30-1903-4 |
| FLT110 w/TMB lens | M115x1.25 | FTF3035B-A | A30-1903-6 |
| FLT110 w/TEC lens | M115x1.0 | FTF3035B-A | A30-1903-6A |
| FLT w/DDG stock focuser | M113.5×1 | FTF3035B-A | A30-1903-6B |
| FLT123 & Megrez 120 | M122x1 | FTF3035B-A | A30-1903-FLT123 |
| FLT132/Zenith Star 126 | M139x1 | FTF3545B-A | A35-503-WOFLT132 |
| FLT151, FLT152, FLT158 | M167x1 | FTF3545B-A | A35-503-WOFLT152 |
| FLT178 | M134x1 | FTF3545B-A | A35-503-WOFLT178 |
| Zenith Star 126 (2nd version) | 4.034″ | FTF3035B-A | A30-1903-24-M |
The 2.5, 3.0, and 3.5″ Feather Touch focusers will need an end cap and we have comp. ring and threaded end caps.