SAWAKE New AC LED Non-Contact Electric Voltage Alert Detector Sensor Tester Pen Stick Safe and easy-to-use, the voltage detector designed for electrical testing, small and compact pen design for easy carrying. Voltage Sensitivity: 90~1000V AC (never test the voltage which is more than 1000AC); Operating Temperature : -10C ~ 50C; Storage temperature: -10C - 50C; Operating Humidity : 80% A necessary tool for everybody who works with electricity, ideal for testing AC cables, circuit breakers, wall sockets, junction boxes, fuses, etc. Touch the wire with the pen tip. If the red indicator lights up, it means voltage exist. Detects voltage without metallic contact. Safe and easy-to-use.