The Peacekeeper Revolver (Philips actually trademarked that name) is one of the only guns of its generation that still works on modern flat tv's. Philips did not invent the gun by itself, but borrowed the design from Sega, who developed the Justifier around the same time. This time, to move the cursor realtime on the screen while you move the gun, Philips licensed the technique of AirMouse. That's mainly because Philips wanted to use full motion video at the same time as the gun, to get games like Mad Dog McCree running on the system. The regular gun techique like the Zapper did not work on CD-i because of technical limitations.
Here you see a Sega Justifier gun modified and run through a converter box to work on a 3DO. This is a precursor of the released Peacekeeper.
The 3DO had the same type of gun. While the technique behind the Peacekeeper Gun
comes from Air Mouse, the same 3DO gun works via a different technique, like the Zapper.
[Thanks, Assembler Games]