The china platter is a piece of Syracuse China made by the Onondaga Pottery Company (O.P. Co.). The "F-12" mark indicates the date of manufacture as December 1955. Manufacturer: Onondaga Pottery Company (O.P. Co.), which later officially changed its name to Syracuse China Corporation in 1966.Pattern: The specific pattern name is likely Greek key band, common for the era.Date of Production: The date code "F-12" corresponds to December 1955. Date codes were stamped in ink on the bottom. Measures 10 in by 7 in, and is in great condition.