Here is a rare and attractive 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. This reference originally sold with a smooth back in 1956 when they were first introduced, and in 1959, Omega added the raise Seamaster emblem on the center of the back. The 20 jewels movement is an Omega calibre 503 with a swan neck regulator. It has been fully serviced and running accurately. The movement serial number is 16978169, dating this watch to 1959. Rare factory original black dial in well-aged condition. Original signed crown. Crystal is brand new—Original Beads of Rice "BOR" 18mm bracelet. The solid stainless steel original case measures 34.3mm, excluding the crown by 41.8mm lug tip to lug tip—case model 2849-15 SC. The calendar feature is working accurately. The wrist size in the photo is 6 inches. This watch including its BOR bracelet will fit up to a 7.5-inch wrist.