The Letter Receiver at Balmain has a newer locking system, two loops on the body with a rod passing through the loops and across an extension on the door and with a padlock. The slot on the door is more visible. The top of the door may have had the next clearance information. The Royal Australian Historical Society is offering a 20% discount on Adel Briggs' book 'Cast Iron - New South Wales Letter Receivers' for users of Flickr. Call the RAHS on (02) 9247 8001 or email admin@rahs.org.au to order your copy and mention Flickr to receive your discount!