These were made for my Holosun 509t to fit the RMR cut on my Zaffiri Precision slide. The slide cut from ZP did not fit the adapter plate that came with the red dot and I was not pleased that it did not co-witness with my sup. height sights.
These adapters are thinned and sets the sight low enough to still utilize the iron sights in case of failure of the red dot. The plate will need to be sanded for perfect fit. I also sanded down the RMR screw lugs on the slide to accommodate the thinner plate.