Unitas 431

The Unitas 431 is a manual-winding Swiss pocket watch movement featuring small seconds at 6:00 in Lépine configuration, where the crown sits at 12:00. When mounted in a hunter case with the crown at 3:00, the dial rotates clockwise to position small seconds at 9:00. It is recognized as a larger variant of the widely used ETA/Unitas 6497. Production has ended, though examples appear in vintage Waltham pocket watches from the 1960s.