You must be logged in and verified to contact the designer.
This version 13 is an improved version of V12 to make a strong attachment for any Bandai DX Macross Variable fighter. But V 13 is compatible In particular the DX Chogokin Macross Delta Sv-262 Draken III which has a special attachment design.
The hole fits a M4 screw and up to a maximum of M5 screw. The space between the 2 arms are 8mm.