Extraordinary Strength • Stainless steel 17-4 metal-injection molded (MIM) construction for strength and durability • Four solid walls for fast, low-friction tooth movement and superior control • Remarkably easy-to-use slide mechanism with deep funnel and backstop for quick wire changes • Smooth slot corners for reduced binding even in severe deflections • Vertical slot for removable drop-in hooks and other auxiliaries • Contoured base design and Optimesh® XRT pads for optimal bond retention