Check the listing for details. Grover-Trophy 10 Window Flip Folio Folder. Condition: New. Listed at 4.99 USD. This TR9400 flip folder is a highly efficient organizational tool designed to meet the needs of marching bands with five double-sided windows so you can display ten pieces of sheet music. Constructed with durable materials, including a sturdy cover and reinforced edges, this folder is built to withstand wear and tear for long-lasting use. Each flip folder comes with five windows and two steel rings to get you started.