Description:  Electrical Tester Pen Digital AC/DC Voltage Detector Non Contact Power Cable Testing Electric Compact Pen Meter 12-1000V Current Electric Sensor Test Pencil.  Specification:  Material: ABS.  Color: Red, Yellow.  Batteries Included: No.  Breakpoint detection. AC voltage sensing. Sensitivity adjustment. Zero line recognition.  Features:  Non contact AC voltage sensing: When a nearby AC voltage is sensed, a Repid beep will sound and the sensor head will flash red.  Accurate test and stable performance, triple alarm with sound and light screen.  Multi-function zero line recognition: Fireline: it will beep quickly when inserted, and the pen tip will flash red neutral line there is no buzzer when inserted, and the pen tip will not flicker.    Usage:  1. Press the position of the black square block.  2. While holding down, push the pen coverup to install 2AAA batteries.  Package included:  1 x Electrical Tester