Note: These fittings are designed to nominally fit the actual ID of the tubing size indicated. To get the correct size fitting, you must measure the ID of your tubing.
| Nominal Fitting Size | OD of fitting |
| 1/8"(3mm) | 3.5-4mm |
| 5/32" (4mm) | 4-4.5mm |
| 3/16" (5mm) | 5-5.5mm |
| 1/4" (6mm) | 6-7.5mm |
| 5/16" (8mm) | 8-9mm |
| 3/8" (10mm) | 10-11mm |
| 1/2" (12mm) | 11.5-13mm |
| 9/16" (14mm) | 14-15mm |
| 5/8" (16mm) | 16-17.5mm |
| 11/16" (18mm) | 18-19mm |
| 3/4" (20mm) | 20-21.5mm |
| 13/16"(22mm) | 22-23.5mm |
| 1" (25mm) | 24.5-26.5mm |
| 1-1/4" (32mm) | 32-34mm |
Note: The smaller (First) number measures the OD of the flat section of the sleeve on the fitting. The larger (Second) number measures the ribbed portion of the sleeve on the fitting, which is slightly enlarged.