Features: Fit for squareD QO or homeliness 150 and 200amp panels. These interlocks are made of aluminum and are sand blasted and then anodized. Our interlocks kit prevents utility and generator supplies from being on at the same time, so you can safely back feed your home electrical needs to a portable generator. Solution for power outages or backup power to keep your home running safely. 1-3/8 inch spacing between the main breaker and the generator breaker. The interlocks kit is specifically designed for easy installation, with a 3/16 "drill bit that can easily penetrate your breaker panel. Specifications: Material:Metal Package Includes: 1Set Generator Interlocks Kit note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.