"45 mm guns" . "45 mm/46 21-K" . "(21-K)" . "21K" . "45 mm anti-aircraft gun (21-K)" . . . . "45 mm 21-K gun" . "''21-K'' gun" . . "''21-K''" . "45/43 40K" . "45 mm ''21-K''" . "''21-K'' AA guns" . . . "45mm/46 cal." . . . . . "45 mm semi-automatic" . "21-K" . . "45 mm anti-aircraft gun (21-K)" . "45mm 21-K" . "45 mm gun" . . "2.3975" . . "41-K" . . . "21-K AA guns" . . "21KM" . . . "21-K AA gun" .