The 3 way - squared corner connector is an external fastening method that is typically used to create a corner connection between three profiles. It is a heavy-duty connection that is simple to use and provides a polished look. The 3 way - squared corner connector requires an end tap machining service on the mating profiles. The suggested hardware can be found on the "Suggested Hardware" tab.
For technical details and images, please search for the product using the 80/20 interactive catalogue found here: https://catalogs.8020.net/80-20-Catalog-26/C/.