Flange Kits, Bolt Hole Size 1.75 in, Compatible Pipe Size 3/4 in, Compatible with Brand Armstrong, Compatible with Series Astro 2, Design Envelope Compass, Compatible with Series Family Astro 2, Design Envelope Compass, Flange to Pipe Connection Type FNPT, For Use With Potable Systems No, Flange Type Standard, Number of Mounting Holes 2, Compatible with Manufacturer Model Number Astro 210CI, Astro 280CI, Astro 280CI - 230V, Astro 286CI, Compass R 20-75