Milan Secondary Air Tube
| FIRE MODEL | SECONDARY AIR TUBE | DESCRIPTIONS |
| Caldo/Firenze/Rad Rustic Harmony /Caldo Harmony/Piccolo Harmony | Secondary Air Tube 01 | 27 Holes, 492mm |
| Signature/Milano/Milano Harmony | Secondary Air Tube 02 |
20 Holes, 598mm |
| Harmony Insert | Secondary Air Tube 03 Front |
20 Holes, 446mm |
| Harmony Insert | Secondary Air Tube 03 Rear |
20 Holes, 446mm |
| Harmony Insert | Secondary Air Tube 04 |
6 Holes, 445mm (Square) |
| Fiorenzi/Euro | Secondary Air Tube 05 |
16 Holes, 435mm |
