Mercury Systems Support GSFA. "Replaces top holder on Guan Sheng/Synta made Dob and focuser including those from Orion (Skyquest & Intelliscope), Hands On Optics, Hardin, Anatares, Skywacher, OPT and others. Gives 2" Brass Compression Ring."
I have an original Orion XT8 Dob (GS), which originally came with a 1.25" focuser only. I upgraded the focuser to a Japanese 2" model. When MSS produced these 2" compression ring screw in replacements I ordered one hoping it may fit my non-standard 2" focuser which it doesn't. It is brand spanking new because it's the wrong size. Also included are the optional Brass Screw Knobs. More information can be had at the web site (Mercury Support Systems - GSFA Adapter).
List price for the ring is $30.00
List price for the screws 2.50
plus shipping charges
Save some cash. My loss is your gain.
$20.00 shipped Priority Mail. Postal Money Order only, CONUS only.