Yeeco -20 to +100 Dual Dispaly LED Digital Thermometer Temperature Monitor Gauge Indoor Outdoor Temp Tester with Dual Display & 2 NTC Waterproof Temperature Sensor Probes (Red & Blue) 0.28" dual LED display temperature tester with two NTC waterproof temp probes Temperature testing range: -20-100; Working temperature: -40-80 Power supply: DC 4-28V; Testing accuracy: 1 about 1s/times refreshing time Size: 45mm*26mm/ 1.8"*1"; Length of the probe: 1m/ 39.4" Great for car, refrigerator, fish pond and air-conditioned rooms temperature testing