Works with Huben GK1 version 1-3, machined aluminum and anodized. There have been several versions of these but the most recent includes secure mounting to new red dot or picatinny back plate. This product is designed to work as a companion add on to the top RMR or Picatinny mount.
Design and made by me here in the US. (Includes 2- M5x25mm Bolts)