Diameter approximately 3.6cm. This is a listing for a Seiko Skyliner Calendar hand-wound men's watch. It was occasionally used from my father's watch collection. There may be stains and minor scratches on the edge of the dial, as well as clear scratches due to use and storage, but the glass surface is relatively clean and in good condition for its age. Please examine the images carefully (there is a reflection of fluorescent light). The belt has been replaced with a non-original mesh stainless steel belt (apparently, it was the belt that was attached when it was purchased used). This belt is free-size, so please adjust it to the appropriate length each time you wear it. It's a hand-wound watch from about 50 years ago, so I cannot guarantee its future operation, but it was running without major errors at the time of listing (based on observation for about half a day). There is currently no issue of it stopping immediately after winding the hand-winding screw (crown). The quick change of the date was switched by adjusting the time and moving the hour hand back and forth between around 3 o'clock and 9 o'clock. ***OH history is unknown... Also, I have not performed any OH maintenance. If you are concerned, please have it repaired and maintained yourself. There are no accessories. I am very sorry, but please do not purchase if you are not familiar with used items, are nervous, do not understand the above explanation, are anxious, or have never handled antique items (especially mechanical ones). Mercari is a place for private sales. It is a used item in its current condition and is inspected by an amateur (there is no 100% perfection), so please understand. ※※ I will ignore and delete consultations using the standard Mercari template without a price offer or price negotiations that lack common sense. Also, please refrain from "likes" if you are not going to purchase, as it will be a factor in removing the listing... #Seiko #SEIKO #SeikoSchoolTime #SEIKOSCHOOLTIME #SCHOOLTIME #SeikoHandWoundWatch #HandWoundWatch #MechanicalWatch #SeikoTomony #Tomony #SeikoMechanical #CITIZEN #Citizen #CitizenMechanical #CitizenHandWoundWatch #SeikoChampionCalendar #SeikoChampion #SEIKOchampion #SeikoSkylinerCalendar #SeikoSkyliner #SEIKOSKYLINERcalendar #SEIKOSKYLINER Movement: Hand-wound