What is the difference between flange adaptor with jointing face with o-ring groove and the flange adaptor combined jointing face flat and serrated, and when we use each flange? - Quora
![2.06 Inch (in) Inside Diameter (I.D.) A-36 Carbon Steel Spacer Plate to Fit Between Fiberglass Pipe and Raised Face Flange - The Marzolf Company 2.06 Inch (in) Inside Diameter (I.D.) A-36 Carbon Steel Spacer Plate to Fit Between Fiberglass Pipe and Raised Face Flange - The Marzolf Company](https://marzolf.com/wp-content/uploads/fiberglass-1-1.png)
2.06 Inch (in) Inside Diameter (I.D.) A-36 Carbon Steel Spacer Plate to Fit Between Fiberglass Pipe and Raised Face Flange - The Marzolf Company
![Flange Faces - Raised Face (RF), Flat Face (FF), Ring-Type Joint (RTJ), Male-and-Female (MF), Tongue-and-Groove (TG) Flange Faces - Raised Face (RF), Flat Face (FF), Ring-Type Joint (RTJ), Male-and-Female (MF), Tongue-and-Groove (TG)](https://www.wermac.org/flanges/flanges_img/flg_ff.jpg)