Fangrui Product Details Compatibility Assurance: Designed To Function Seamlessly For Cutler Hammer Br And Ch Series Main 150 And 200 Amp Panels, Ensuring A And Faultless Operation. This Vital Compatibility Eliminates Issues During Installation Or Use, Enhancing Your Safety And Convenience. Precision Spacing Requirements: Requiring A Precise Interval Space Of 1 1/4 - 1 7/16 Inches Between The Main And Generator Breaker, This Kit Ensures Safe Operation. Precisely Measuring The Spacing Is Critical For Optimal Performance Double-check Model Numbers And Dimensions For A Setup. Enhanced Safety Features: Equipped With A Manual Transfer Switch Device, This Kit Ensures The Safe Back-feeding Of Power From A Portable Generator To Your Panel And Home Lines. It Effectively Prevents Both Utility And Generator Supplies From Being Active Simultaneously, Safeguarding Against Electrical Hazards And Equipment Damage. Colour:silver Material:metal Package Contents: 1 x Generator Interlock Kit(drill Bit Color Is Random, No Specification Is Accept Note: 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.