The Cose Metal Buckle with Rectangular Slider, 31mm in silver, is a rectangular frame-shaped metal buckle used to adjust the length of straps and belts without a locking function, only a sliding mechanism. The 31mm size is an intermediate variation within the range, suitable for straps with a width slightly different from the 30mm reference. It is an essential accessory for those who make bags, backpacks, and adjustable belts with a more robust finish than conventional plastic.