Helps with safe ladder positioning on uneven surfaces. Automatically locks in position after the ladder is positioned. Maintains duty rating of the ladder up to Type IAA 375 lb. rated. Sold as a pair and comes with instructions and hardware to install. You will need a drill, a 3/16" drill bit, a 1/4" drill bit, a hacksaw, and two 7/16" wrenches. Aluminum housing with steel spike shoe. Proudly made in the USA