51 五一 (WuYi) is May 1st, the date chosen to be the brand name of Tianjin's first mass-produced watches. The 62-A was the second generation of 51 watches, and was available with both stainless steel and plated cases. The movement inside was modeled after the FHF 25/28 series, and it is probable that it was manufactured on machinery purchased from the Swiss Fabrique d'Horlogerie de Fontainemelon.