Made in the USA ! Interlock prevents breaker panel main breaker and generator breaker from being turned on at the same time, preventing a potentially deadly backfeeding of the utility line. Lifetime Warranty Includes Everything Required For Installation Precision CNC Machined From Solid Billet Aluminum Color Anodized for Smooth Operation and Lifetime Corrosion-Proof Appearance This interlock kit fits Siemens and Murray 150 and 200 AMP panels with single horizontal throw (left-right) main breaker as shown, and 7/8” to 1 1/4” spacing between main breaker and first branch circuit breaker cutouts. These kits are very high quality. The interlock is CNC machined from solid billet aluminum, then sandblasted and color anodized so they operate smoothly and won't corrode like many others. They include everything you need to complete the interlock installation including the correct size quality HS steel drill bit, a tube of name brand thread lock compound, a complete set of vinyl weather resistant labels and placards, and very clear installation instructions. Our kits look professional and they make you look professional. One you use one of our kits you won't want to use anything else!