The Brother SF-4000 Stapler Finisher adds new paper output functions to your Brother printer including stapling, offsetting, and stacking. Personalize these functions in the printer driver, from the printer's LCD, or using the printer's Web Based Management page. This optional accessory can staple up to 50 pages and has an output capacity of 500 pages, with an offset up to 50 pages for easier collating. When the standard output tray is full, the printer will automatically switch to the SF-4000 output tray, increasing the printer's output capacity up to 750 pages.