This adapter is a push-in style for the P-FLAT6AIII.
It Can Not Support Twenty Years Anniversary Edition.
Side A: M63 (female).
Side B: 2-Inch barrel, Push-in Adapter for P-FLAT6AIII, and the end of the 2-inch barrel has 48 mm (female) threads.
With this 2-inch adapter and FLAT6Alll together ,it will work for most 3-inch to around 4-inch refractors, f/6.5 to about f/8 APOs that have 2-inch barrel openings.