What is the Difference between P600 Series (P620, P640 & P660) Cameras?

FLIR P660	FLIR P640	FLIR P620
• <30 mK sensitivity at an accuracy of +/- 1% • Standard "optional lens" • Wide range of lenses • 8x digital zoom • Extended measurement functions • USB and Firewire connection • Sequence recording in camera • Built-in GPS • Contrast Optimizer • Automatic Laser Alignment	• 30 mK sensitivity* at an accuracy of +/- 2% • Standard "optional lens" • Wide range of lenses • 8x digital zoom • Extended measurement functions • USB and Firewire connection • Sequence recording in camera • Upgradable to FLIR P660*	• 40 mK sensitivity* at an accuracy of +/- 2% • Standard 24° lens • Wide range of lenses • 2x digital zoom • Standard measurement functions • USB connection • Upgradable to FLIR P660*