The Cose Rectangular Buckle with Slider, 30mm in black, is a rectangular frame-shaped plastic buckle used to adjust the length of straps and belts without a fastening function, only a sliding mechanism. Black is one of the most versatile colors in the range, suitable for backpacks and accessories of any style. It is an essential accessory for those who make backpacks, bags, and adjustable straps in handcrafted leather goods.