AEDIKO 4pcs DC 5V Relay Module 2 Channel Relay Board with Optocoupler Support High or Low Level Trigger 2 Channel 5V auspowers_batchtwo LG and laptop car charger 99 inches 203mm 2M LG and laptop car charger for MacBook Read more 2 functions in one unit: Open phase indication & Phase rotation indicationCheck the presence of open phase and 3 phase sequence condition Fast and accurate measurement Indicate direction of rotation Ensures the object being tested is not damaged from incorrect wiring With simultaneous indications via LEDs and audible buzzer sound Indicate phase orientation (Clockwise or counter clockwise) and whether each of 3 phases is live Portable and compact design Specifications This is a very useful instrument for checking the phase sequence with indication by LED's and Buzzer at the same timeIt is featured with the fast and ccurate measurement to check of the presence of open phase and phase sequence condition Operation Voltage : 60V ~ 600V AC Relay Status Indicator (Red)Module Size : 50mm 26mm 18 2”x 1”x 0