Be sure to read the testing instructions carefully. This is the cheapest place I could buy them and all 9 worked perfectly. As mentioned above, when testing a closed circuit, hold down the test button AND hold it down while testing the open circuit breakers. This time you need to read the instructions.
Electricity Monitor Voltage Overload Protection
8 Review
π GE 150 or 200 Amp Main Breaker Generator Interlock Kit - 1 1/4 Inch Spacing Between Main and Branch Breaker
7 Review
π Interlock Kit for Generators with Cover and QOM2 Frame Size Main Breaker Interlock Kit
8 Review
π‘ Professional Generator Interlock Kit: Compatible with Square D QO or Homeline 150/200 Amp Panels, 1 3/8" Spacing Between Main and Generator Breaker
7 Review
π‘ Hydrofarm Quantum QT400 Dimmable Ballast for 400W Grow Lights
5 Review
Wireless Electronic Ballast Interface Certified
8 Review
Fulham WorkHorse WH2-120-C Adaptable Ballast - 2 Pack
3 Review
π‘ Electronic FL Ballast ICN-4P32-N (Formerly ICN-4P32-SC) for 3-4 F32T8 F40T8 F17T8 Lamps, 120V/277V Compatibility
5 Review