Ideal Vacuum | ISO 100 Centering Ring Stainless Steel with Viton O-Ring No Spacer, NW-100 Vacuum Flange Size, Typically Used with 4 Inch O.D. (101.6 mm) Tubing
ISO Centering Ring with O-ring and Spacer – High Vac Depot
O-ring Spacer .24" (6.1mm) inside dia EPDM Black Rubber - VCC
Coffman's Replacement Snap Ring, Spacer, and O-Ring