Series Model: ML-4550 / 4551N / 4551ND - High speed Laser Printer: Up to 43 ppm in A4 (45 ppm in Letter), Duplex: 29 ipm (A4); 30 ipm (Letter) - Resolution: Up to 1200 x 1200 dpi - Marvell 500Mhz - Memory: 128 MB (Max. 512 MB) 128, or 256 MB optional memory available. Use only the Samsung-approved DIMM. 128 MB: ML-MEM150, 256 MB: ML-MEM160 - Option: ML-4550:500-sheet trays, ethernet 10/100 Base TX wired LAN, ethernet 10/100 Base hard disk, duplex unit, DIMM - Toner cartridge: Starter: 10K or 20K pages Consumable: 10K or 20K pages - Duty cycle: Monthly Up to 150,000 pages