Angled lie-flat seats recline 170 degrees (or slightly less) to provide a flat sleeping surface, but are not parallel to the floor of the aircraft when reclined, making them less comfortable than a bed. Seat pitch typically ranges from 55 to 65 in (140 to 170 cm), and seat width usually varies between 18 to 23 in (46 to 58 cm). These seats first appeared on Northwest, Continental, JAL, Qantas and several other airlines in 2002 and 2003.[16] Fully flat seats recline into a flat sleeping surface which is parallel to the floor.