uxcell 3Pcs AC100-500V 3mm Slotted Voltage Tester Pen Electroprobe Voltage Tester is perfect for directly or indirectly testing AC voltages. Right usage is only way to get good performance It is suitable for use to home, shop, garage, automotive, motorcycles, boats,ect. A good accessory help a good co-worker measure electrician. It also be used for other products voltage and current measurement purposes.