This part fits the following boilers:
| Fits Appliance(s) | GC No. | |
| Ferroli Optimax HE 18 Ov | - | 41-267-28 |
| Ferroli Optimax HE 18 S | - | 41-267-27 |
| Ferroli Optimax HE Plus 18 Ov Rev 1 | - | 41-267-29 |
| Ferroli Optimax HE Plus 18 S | - | 41-267-31 |
| Ferroli Optimax HE Plus 25 Ov | - | 41-267-30 |
| Ferroli Optimax HE Plus 25 S | - | 41-267-32 |
| Ferroli Optimax HE Plus 31 C | - | 47-267-44 |
| Ferroli Optimax HE Plus 35 S | - | 41-267-33 |
| Ferroli Optimax HE Plus 38 C | - | 47-267-45 |