2x Bino Vue Amplifier + BVC-0125. This amplifier includes filter threads requiring a BVC-0125 adapter/coupler (included) between the Bino Vue body and the 2x amplifier.
The coupler is required to assure that the 2x amplifier does not allow the filter to contact the mirror in a 2" TeleVue diagonal.
To prevent this from happening:
1. Use a TeleVue "high-hat" 2" to 1.25" adapter***
2. Remove the .75" long black nosepiece that couples the 2x amplifier to the Bino Vue body
3. Re-install using the supplied flat coupler BVC-1025
***Note: in some telescopes, you may not have enough in-travel to reach focus with the flat coupler installed. In that event, replace the 2" to 1.25" high-hat adapter with a flat-top version (ACF-2125) which allows more in-travel while still preventing a filter from contacting the mirror in a 2" diagonal.