End Fasteners Assemblies are an economical way to make 90° connection between two extrusions.  Moderate strength connection that is completely hidden. The winged tabs of the clip prevent the mating profile from rotating. This connection method requires two machining services; an end tap on the mounting profile and an access hole in the mating profile in order to reach the screw head.
 
Assembly includes
(1) End Fastener Clip
(1) 5/16-18 x 1.00" Button Head Cap Screw