FNPT stands for Flight & Navigational Procedures Trainers. The I and II are different levels then there is also a FNPT II MCC which stands for Multi Crew Co-operation training. These are all identifications given by the JAA and are considered 3A devices.
Devices are further categorized by:
JAA-STD 1A - Full flight Simulators
JAA-STD 2A - Flight Training Devices (type specific no motion)
JAA-STD 3A - FNPT
JAA-STD 4A - Basic Instrument training Devices (also known as PCATD in the US which are devices on PC's)
Then there are also levels for Helicopters but dont want to bore you with them
