This is from the 1980s, when Filofax was a big hit. It's a 4 CLF 5/4 model. The ring diameter is about 3 cm (5/4 inch). The small, elegant "filofax" logo (photo 12) is quietly becoming a trend. The later models have a large, flashy "filofax" logo. Many users left Filofax because of that later model's logo. I used it to store used refills. It was never taken out of the study. The leather surface will develop a mirror-like finish over time. The plastic cover on the snap fastener came off, so I used a car paint repair pen to paint the metal part of the fastener (photo 15). It can be used without any problems even if the paint comes off. Please enjoy this rare and evolving Filofax.