FLAT68III longer adjusting adapter for WIFD GT81-M48
To use this adapter, simply unscrew the original end adapter that terminates in the M48 male thread on the flattener and replace it with this longer adapter.
The correct back focus setting specifications for the P-FLAT68III with GT81 WIFD telescope is 2mm.
This is part# AD-M80-54-M48
Male thread: M48x0.75
Female Thread: M80x0.75