The lower the micron rating, the finer the filtration. Follow your engine manufacturer's recommendation for fuel filter micron rating.
S = Secondary/Final 2 micron (Brown cap)
T = Primary or Secondary/Final 10 micron (Blue cap)
P = Primary 30 micron (Red cap)
| Brand | Racor |
| Case | 6 |
| Color | Red |
| Fits | 4120R/6120R |
| Micron | 30 |