These boxes are designed specifically to hold Duo-Fast® No. 5418 Electric Tacker Staples. They are made from durable plastic telescoping square tubes that have a detented internal closure mechanism to hold tight when closed. It protects the boxes and staples from falling apart in your tool box. Saving staples saves money! Duo-Fast® is a registered trademark of the Duo-Fast® corporation. Net weight: 2 oz.