I really must say it was hard decision to list this Omega Seamaster Calendar because it has a very nice original dial. It runs very well and smooth actions in all positions of the crown. The date flips at midnight and changes as it should. The case is gold capped and has signs of wear. It measures approximately 34 mm and 42 mm lug to lug. Most of the wear is on the lugs. The caseback features the Omega Hippocampus and is favored among collectors. It has a nice clean 503 Cal Omega movement. I added a nos JB Champion leather band. Nice and supple still and is the same vintage of the watch. The watch has its original marked in the center crystal and the crown is original as well. All the more reason I'm having a hard time letting this one go. I simply have too many watches and can't possibly enjoy them all. My loss is your gain please feel free to contact me with any questions. I'm sorry but I'm unable to change the silly Mpn number saying the Cal is 1020 when it is most certainly not. eBay has some issues sometimes but I assure you it's a 503 like the one pictured