| Code | external diameter imperial tube | |
inches | mm | |
| SFF-1 | 1/16" | 1.59 |
| SFF-2 | 1/8" | 3.17 |
| SFF-3 | 3/16" | 4.76 |
| SFF-4 | 1/4" | 6.35 |
| SFF-5 | 5/16" | 7.93 |
| SFF-6 | 3/8" | 9.52 |
| SFF-8 | 1/2" | 12.70 |
| SFF-10 | 5/8" | 15.87 |
| SFF-12 | 3/4" | 19.05 |
| SFF-14 | 7/8" | 10.22pm |
| SFF-16 | 1" | 25.40 |
| SFF-20 | 1-1/4" | 31.75 |
| SFF-24 | 1-1/2" | 38.10 |
| SFF-32 | 2" | 50.80 |
| Code | external diameter metric tube |
mm | |
| SFF-2M | 2 |
| SFF-3M | 3 |
| SFF-4M | 4 |
| SFF-6M | 6 |
| SFF-8M | 8 |
| SFF-10M | 10 |
| SFF-12M | 12 |
| SFF-15M | 15 |
| SFF-16M | 16 |
| SFF-18M | 18 |
| SFF-20M | 20 |
| SFF-22M | 22 |
| SFF-25M | 25 |
| SFF-28M | 28 |
| SFF-32M | 32 |
| SFF-38M | 38 |