Comparison : Item # 211-061-10, 10 Millimeter (mm) O.D. Tube Polyethylene Metric Tube Compression Fitting Insert
Item # 211-061-15, 15 Millimeter (mm) O.D. Tube Polyethylene Metric Tube Compression Fitting Insert
Item # 211-061-22, 22 Millimeter (mm) O.D. Tube Polyethylene Metric Tube Compression Fitting Insert