This beautiful and scarce sword belt plate dates ca.1835-1845. Measurements are 49 x 91 mm. It's identical to the belt plate pictured in the O'Donnell and Campbell's book, pl.287, p.194. According to the authors this pattern was produced by the Ames Company from the 1830s to mid-1840s. Plate is struck twice with a number 25, as well as SS.
An outstanding, well-made, high quality piece dating back to the Mexican War, in collector's choice condition.