This is a stapling finisher accessory for Lexmark's MS911, MX91x, CS92x and CX92x printer/MFP series — an add-on unit that attaches to a compatible Lexmark device to automatically staple finished print jobs before they leave the output tray. The "2:4 Staple" designation indicates it can apply either a 2-staple or a 4-staple finish depending on the job settings, useful for producing ready-to-distribute stapled reports, handouts or booklets straight off the printer without manual finishing. It's a finishing accessory rather than a standalone printer, and only works when paired with one of its listed compatible Lexmark models.