0-20mm Replacement O-Ring Kit, TFE Stem, Viton, To Consist Of: 1ea: #208 2ea: #210. Each kit contains a set of three o-rings, one for the tip and two for the barrel seal. O-ring sizes are listed in the following chart. If individual o-ring is required see CG-305 for Viton or CG-308 for Kalrez.O-Ring Specifications:0-20mm: #208 Tip O-Ring, #210 Shaft O-Ring