APM Telescopes. TS-Optics CNC Aluminium Tube Rings for telescopes with 114mm diameter
85mm PLUS support rings: Buy online | Primalucelab.com
PrimaLuceLab Guide rings PLUS 80mm
More Blue 80mm Tube Mounting Rings | First Light Optics
Antares Telescope Tube Mounting Rings - 3.5" (90mm) (Set of 2) for many 80mm Refractors (Same as Orion) - Camera Concepts & Telescope Solutions
Amazon.com : Astromania Adjustable Guiding Scope Ring Set with Plate - 80 mm Inside Diameter (Pair) - for Telescope Tube Diameter or Finders 53 to 79mm : Electronics