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