A very distinctive and attractive duplex cancellation used only in Edinburgh  Greenock & Dundee - and distinguished by the circular outer rim of the datestamp cut into a number of arcs. A number of different types exist and type differs through the number of cuts to this outer arc. Examples other than used on the 1d red are unusual and examples on overseas mail are rare. The essential book is  'Dotted Circle Cancels' by Arundel and is available from our book section for £20.00 plus postage.