The HP LaserJet 4 Plus series of printers provide 600-dpi resolution and built-in Resolution Enhancement technology (REt) with a throughput of up to 12 pages per minute. ??It has scalable fonts, hot I/O's, dual-bin input, enhanced PCL 5 Language, HP's new Memory Enhancement technology (MEt), and the HP-GL/2 enhancement for plotter output. It also has an optional duplex unit, optional envelope feeder, and optional output stacker.