The Series 65 Heat Detector monitors temperature by using a dual thermistor network which provides a voltage output proportional to the external air temperature. There are four classes of heat detectors in the Series 65 range designed to suit a wide variety of operating conditions.
Approvals: AS 7240.5-2004

| Voltage | 9-33 VDC |
| Quiescent Current | 45µA at 24 VDC |
| Alarm Current | 52mA at 24 VDC |
| Operating Temperature | -20°C to +90°C (no icing) |
| Relative Humidity | 0% to 95% (non condensing) |
| IP Rating | IP23D (EN60529) |
| Size (inc Base) | 100mm Dia x 50mm H |
| Weight (inc Base) | 131 grams |
| 4106-1004 | Series 65 A1R (50°C) Heat Detector - Rate of Rise |
| 4106-1005 | Series 65 BR (65°C) Heat Detector - Rate of Rise |
| 4106-1006 | Series 65 CR (80°C) Heat Detector - Rate of Rise |
| 4106-1007 | Series 65 CS (80°C) Heat Detector - Static |