The 4445 Voltage Detector Tester provides the most convenient and reliable means of verifying operation of Salisbury Voltage Detectors. The tester features instant push-button operation and requires a standard 9-volt battery (included). It’s portable and lightweight. To operate, push the button and move the tester toward the voltage detector being verified. The tester generates an electric field that activates the detector verifying the audible and visual signals are operational.Features & Benefits:● Test Procedures● To assure unit is in operable condition switch tester into “Test-240V” position. The tester may now be tested in several different ways.● Place head as marked against live wire outlet or equivalent above 110V A.C. ● Rub the head as marked on cloth or clothing to obtain static charge. Unit will only indicate intermittently.