| 20 mm (0.79 in) | Match the measured diameter; allow only the fit clearance specified by the heater maker | 20–25 mm (0.79–0.98 in) | 120 V or 240 V, as supported by the machine | 75–150 W | For compact nozzles, check that the heater clears the nozzle shoulder and nearby tooling. |
| 25 mm (0.98 in) | Match the measured diameter; verify the heater’s stated fit tolerance | 20–30 mm (0.79–1.18 in) | 120 V or 240 V, as supported by the machine | 100–200 W | A narrower heater may suit limited space; choose width based on the heated area and available clearance. |
| 30 mm (1.18 in) | Match the measured diameter; do not rely on nominal machine size alone | 25–35 mm (0.98–1.38 in) | 120 V or 240 V, as supported by the machine | 150–250 W | Check the nozzle’s cylindrical contact area so the heater sits flat and does not overlap a shoulder. |
| 35 mm (1.38 in) | Match the measured diameter and confirm the required clearance | 25–40 mm (0.98–1.57 in) | 120 V or 240 V, as supported by the machine | 175–300 W | Compare wattage with the machine’s control output and the original heater rating. |
| 40 mm (1.57 in) | Match the measured diameter; confirm the inside-diameter tolerance with the supplier | 30–40 mm (1.18–1.57 in) | 120 V or 240 V, as supported by the machine | 200–350 W | Consider nozzle mass, target temperature, heat loss, and warm-up time when selecting wattage. |
| 45 mm (1.77 in) | Match the measured diameter and check for a close, even fit | 30–45 mm (1.18–1.77 in) | 120 V or 240 V, as supported by the machine | 250–400 W | Verify that the wider band does not interfere with the mold, guard, wiring, or adjacent components. |
| 50 mm (1.97 in) | Match the measured diameter; use the heater maker’s fit specification | 35–50 mm (1.38–1.97 in) | 120 V or 240 V, as supported by the machine | 300–500 W | Check current draw, controller capacity, and terminal or lead clearance before installation. |