Flat Face O-Ring (FFS)
SAE J1453
Sealing – The seal takes place by compressing the O-Ring onto the flat face of the female. The threads hold the connection mechanically.
| Inch Size | Dash Size | Nominal Thread | Male Thread OD (inch) | Female Thread ID (inch) |
| 1/4 | -04 | 9/16×18 | 9/16 (0.56) | 17/32 (0.51) |
| 3/8 | -06 | 11/16×16 | 11/16 (0.69) | 5/8 (0.63) |
| 1/2 | -08 | 13/16×16 | 13/16 (0.82) | 3/4 (0.75) |
| 5/8 | -10 | 1×14 | 1 (1.00) | 15/16 (0.93) |
| 3/4 | -12 | 1-3/16×12 | 1-3/16 (1.19) | 1-1/8 (1.11) |
| 1 | -16 | 1-7/16×12 | 1-7/16 (1.44) | 1-3/4 (1.36) |
| 1-1/4 | -20 | 1-11/16×12 | 1-11/16 (1.69) | 1-5/8 (1.61) |
| 1-1/2 | -24 | 2×12 | 2 (2.00) | 1-15/16 (1.92) |
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