The HP LaserJet 8100 is available in three configurations.

HP LaserJet 8100
The HP 8100 comes standard with 16 MB RAM and two 500-sheet trays.
HP LaserJet 8100 N
The HP 8100N comes standard with 16 MB RAM, an HP JetDirect card for connecting to a network, and two 500-sheet trays.
HP LaserJet 8100 DN
The HP LaserJet 8100DN comes standard with 24 MB RAM, an HP Jet Direct card for connecting to a network, a duplexer, and two 500-sheet trays.