A variety of functions, including zero-fire line identification, electrical on/off detection, line breakpoint location finding, sound and light alarm functions. Zero line green light on, fire line red light flashing and beeping sound. Along the line detection, the LED green light on the line smooth and good; LED does not light is the line disconnection point. There is a built-in intelligent motherboard chip in this power meter pen, professional upgrade chip control program compatible safe electricity use. It has LED high brightness color light, still clearly visible in the sunlight. Humanized pen clip design, easy to electrical maintenance and carry. It is suitable compatible maintenance electrical testing, screwdriver assisted. It is constructed of abs material. The length of this product is 13.8cm and width is 1.9cm. It can be used in a wide range of applications such as electronic factories, electrical appliances, car repair, and homes. Item Name: Test Pen Material: ABS Features: LED Double Light, Sound and Light Alarm, Compact, Durable Model: B14 LED Light Beads: High Brightness Dual-color Light Beads Buzzer: Sound and Light Alarm Measurement Range: Voltage 24-250V Shell Material: ABS Insulated Shell Batch Head Material: Chrome Vanadium Steel Power Supply: 3 x AG3 Button Batteries(Batteries Included) Product Functions: Zero-fire Line Identification, Line Breakpoint Judgment, Electrical On-off Detection Size Details: L: 13.8cm/5.43", W: 1.9cm/0.75"(Approx.) Notes: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Tip: Screwdriver electric pen installed after the battery needs to self-test, one hand to hold the pen, one hand to touch the copper hat, light up green light compatible full power, not light or faint light compatible the battery low power. Package Includes: 1 x Test Pen