The shell size is DA (the standard 15-position D-Sub footprint), and the housing comes with an unthreaded flange — meaning you supply your own hardware for panel mounting. The black glass-filled nylon body and tin-plated steel shell give it the mechanical rigidity and EMI shielding expected from a standard D-Sub.
The 205205-2 is the 15-position receptacle housing. Its sibling 205203-2 is the 9-position version (shell size DE) in the same AMPLIMITE HDP-20 series, same unthreaded flange, same free-hanging mount. The only difference that matters for selection is the position count — 15 vs 9 — which drives the shell size and the board cutout. If your BOM calls for 15 circuits, the 205205-2 is the correct shell.