Hewlett Packard Power Envelope Feeder For Laserjet 5/5M/5N. The Hewlett-Packard power envelope feeder allows you to print up to 75 envelopes at a time with your HP LaserJet 5/5M/5N. It supports all standard envelope sizes including 10, Monarch, DL, C5, B5, and more. When teamed up with your LaserJet, the power feeder can crank out nine envelopes per minute. Installation is easy; you simply slide the tray into your LaserJet and you're ready to go.