Hewlett-Packard printers can be transformed into a single-unit copier, fax and scanner with the HP LaserJet Companion accessory. Weighing only 1.36 kilograms, the unit is a parallel pass-through device that hooks up to - and is small enough to fit between - a PC and printer. The Companion scans paper ranging in size from business cards to newspaper-length documents and has a multiple-page document feeder that can handle 10 to 15 sheets, depending on thickness. It has a 256-level greyscale and is compatible with most PC fax modems and software, enabling users to scan documents, then fax them electronically. The copier functions are capable of producing high-quality reproductions with reductions and enlargements of 25 per cent to 400 per cent. The Companion also features Visioneer's PaperPort software that allows scanned documents to be transferred to word processors for editing. HP printer series LaserJet 4, 5, 6 and 6L are compatible with the accessory, which requires a 486 PC or higher with 8 megabytes of RAM, a parallel port, and PC/fax modem and fax software. The price is $1,828.