You will find the Medal for this Ribbon as No.169 in The Medal Year Book.

Not everyone seems to know this......but the Colours of the Ribbon are Green and Red to denote Starboard and Port of a ships Steaming Lights........In this case the ship would be coming towards you......As Port is the Left hand side of the Vessel!!!!
"Quartermaster's Comment":- The Medal came out in 1919. Some 133 000 were issued.