F.O.I.L. Alarm System
This was an alarm system that used a fiber optic cable and was powered by a 9V battery. The cable was looped around some object and inserted into the alarm unit using the ignition key. If the cable was cut or pulled out the alarm sounded.
Clever idea, but the cable couldn't stand being rolled up tightly and crammed into the tool box, and they failed regularly and early. Replacements cost around $150. Honda sells a little metal plate that can be used to cover the space left if you remove the unit, at least for Magnas. It's a pain to install, since you have to remove the auxiliary fuel tank to get to the bolt holding the alarm unit.
(Have a better image? PLEASE attach it.)