AUDAC CHB196 Built-In Speaker Stand Flange for 35 mm Poles

The CHB196 is the socket that goes into the speaker, not the stand. It is an aluminium flange adaptor recessed into a cabinet so a 35 mm pole seats 2.95 inches inside the box rather than clamping to the outside of it. That geometry is what keeps a pole-mounted top box vertical under load instead of rocking on a surface bracket.

It is rated for 77.16 lb and weighs 0.33 lb itself, and is supplied in black or white to match the cabinet it is fitted to. Specify the finish when ordering; the two share every other dimension.