English: The fin and equipment masts of the Oberon class submarine HMAS Onslow
From right to left, the masts are: attack periscope, search periscope, radar mast, electronic support measures (electronic warfare) mast, and the snort induction (diesel generator air intake) mast. Not seen are the wireless telegraphy mast, and the snort exhaust (diesel generator exhaust) mast.[1]