Here is a Omega Seamaster Automatic Calendar watch. This automatic calendar watch is the third generation of the "Seamaster Calendar" model, and it is the first Omega Seamaster model to carry a calendar disc for the 3 o'clock position. The 20 jewels movement is an Omega caliber 503 with a swan neck regulator. It has been fully serviced and running accurately. The movement serial number is 17072437, dating this watch to 1959. Uncommon luminousless original dial in well-aged condition. Original signed crown. Crystal is brand new—brand new 18mm matching high-quality genuine leather strap. The solid stainless steel original case measures 34.2mm, excluding the crown by 42mm lug tip to lug tip. Case model 2849-10 SC. The calendar feature is working accurately. The wrist size in the photo is 6 inches.