When talking about red dot sights, the most commonly used footprint is the Docter/Noblex standard. It contains two holes for screws and four sockets to hold the pins on the mount/adapter, one in every corner. Currently, there is a wide variety of mounts for this footprint, which is one of the main reasons why it is used by numerous manufacturers. Docter/Noblex standard is easy to use and reliable.
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*The red dot sights have a Docter/Noblex footprint, but the adapter provided has threaded sockets that are broader than adapters intended for a Docter/Noblex footprint. Ergo, thicker screws are included. These red dots can be mounted on an adapter intended precisely for the Docter/Noblex footprint, but the provided screws are not useful – thinner screws are required.