Pristine tube ring: $150.
Adapters (if needed):
--Losmandy Male-to-Male Dovetail (DMM)with two holes drilled and tapped for Tak Ring (underneath ring in photo below). $70.
--Super Polaris adapter plate(?); again with two drilled and tapped holes for Tak ring--also recessed for better seating. Outside 1/4 X 20 hand knobs are spaced 161mm (6-11/32") apart. $45.