Blue indicates proximity to AC Voltage source; Red indicates you"re at the source; Operating temperature 0 deg C to 50 deg C; Ultra-Bright White LED; 100,000 hr bulb --- The new LVD2 Light, the newest version of the popular non-contact AC voltage detector and LED flashlight combined in one convenient, compact design. With exclusive dual-sensitivity the voltage detector glows blue when it"s near AC voltage, and glows red when it"s at the source. Detects voltages from 90 V AC to 600 V AC. Voltage detector glows blue 50 Hz - 60 Hz or 2.5 - 38 cm (1 - 5") away from source.