HP LaserJet Pro 400 color Printer M451dn, LaserJet. Maximum resolution: 600 x 600 DPI, Print technology: Laser, Maximum duty cycle: 40000 pages per month. Print speed (black, normal quality, A4/US Letter): 21 ppm, Print speed (colour, normal quality, A4/US Letter): 21 ppm, Time to first page (black, normal): 17 s. Internal memory: 128 MB, Maximum internal memory: 384 MB. Processor clock speed: 600 MHz. Standard input capacity: 250 sheets, Maximum input capacity: 550 sheets, Multi-Purpose Tray capacity: 50 sheets