Vintage Opera Glasses / Field Binoculars

This item is a pair of vintage, compact opera glasses or field binoculars, likely from the early to mid-20th century. They feature a monocular style construction, where the two objective lenses are presented side-by-side without a central hinge, and are housed within a rectangular, possibly collapsible or sliding, casing. The primary material appears to be a polished metal, likely brass or nickel-plated brass, given the reflective, silver-toned surface and visible patina. There are distinct signs of wear, including tarnishing and minor abrasions on the metal surfaces, consistent with age and use. The casing exhibits a textured or engraved finish on the top surface, contrasting with the smooth, polished sides. The lenses are dark and appear to be in reasonable condition, with no obvious cracks or severe scratches visible from this angle. A key identifying feature is the inscription "25x25%" centered between the objective lenses, which could denote magnification or a specific model number, although '25%' is an unusual designation for magnification. This marking is engraved or stamped into the metal. Below this, there appears to be a small circular knob or dial, possibly for focusing. The overall construction suggests a piece designed for portability and a degree of discrete use, common for theatre or sporting events. The patina and style point to an age consistent with the era of such viewing instruments becoming more widely available and popularized. The craftsmanship appears to be functional and robust, though it lacks elaborate decorative elements, suggesting a utility-focused design.