The Sigma 17-50mm f/2.8 EX DC OS HSM Lens is a high-quality zoom lens designed for Pentax mount cameras. With a maximum aperture of f/2.8, this lens allows for excellent low-light performance and beautiful bokeh. The lens features both auto and manual focus options, providing versatility for photographers. Made with durable plastic exterior material, this lens is built to last. It comes with a hood and is compatible with 77mm front lens filters. The Sigma 17-50mm f/2.8 EX DC OS HSM Lens is a reliable choice for Pentax photographers looking for a great zoom lens for their kit.