This is the one I've used 95% of the time. It's an ATS short body coupling between the Tuarus body and rear threads of 10" and larger SCTs (not the 3.25" thread). Does not allow the Taurus reducer to be used, but the various 6.3 reducers can still be used. You can use this as an extra coupling when you don't want to take the time to unscrew the 4 screws that hold the reducer lens. I don't think Taurus has these on their site.
$20 shipped. If it doesn't meet your needs, send it back for a refund. Cas, MO, or check, no wait with good ratings.