The Triplett ET350 (for US use) combines a Non-Contact Voltage and a Magnetic Field Detector. It has dual AC voltage ranges: 24 to 1000V and 90 to 1000V with high sensitivity that allows it to detect low voltage AC wiring commonly found in doorbell circuits, thermostats, control circuits, and video surveillance camera power. In addition, you can quickly determine the presence of magnetic fields (AC/DC/Permanent). CAT IV 1000V safety category and meets cETLus and CE. Includes (2) AAA batteries. 1-year warranty.