The Cose Metal Buckle with Rectangular Slider, 20mm in size and black, is a rectangular frame-shaped metal buckle used to adjust the length of straps and belts without a fastening function, only a sliding mechanism. The black finish gives it a discreet and versatile look, suitable for bags and backpacks of any style. It is an essential accessory for those who make bags, backpacks, and adjustable belts with a more robust finish than conventional plastic.