Is your letter tray piled high with papers? Struggling to fit much more in? What you need are metal connectors to give you extra space. If you add four of these longer length risers in-between each tray, it will give you a clearance of 150mm. You will be able to store additional items in your plastic trays without them overflowing, so there's no need to worry about losing papers down the back of your desk. These metal risers are designed to fit all Avery Stacking Trays. You can also choose shorter risers if you need less space.