Pendaflex SureHook Reinforced Extra Capacity Hanging Box Files feature SureHook Technology with built-in tension springs, ensuring folders stay on track and slide with ease. These letter-size folders come with flexible closed sides and polylaminated tops to safeguard contents. Each box includes a Pressboard reinforcing-bottom insert, 1/5-cut tabs, and printer-ready blank white inserts. With a 2-inch expansion and a two-tone stock design, these blue files are sold in a quantity of 25 per box.