I bought these to replace a broken banister post that broke after 51 years of use assuming the dimensions were identical. It's not like this. The mounting holes for the post and U-bracket under the rail are different from the old ones. The biggest design flaw is the U-bracket, which is so narrow that the entire unit cannot be adjusted for even a slight difference in rail angle. I solved this problem by using an old U-Bracket. The distance from the wall to the center line of the track is also different, causing the track to flex slightly inward. The base metal of the plated mount is non-magnetic, so it appears to be zinc alloy. any type that does not have shear strength. As I approach 80, my dependency on railings will increase in direct proportion to my age. Walking up and down the stairs to the basement about a dozen times a day puts more and more strain on the trestles every day. If I were to order brackets again I would spend more time checking dimensions and base metals.