Spare parts for that system.
If those sprinklers had any trace of nitrogen compounds on them, and the detector was set to maximum gain, it would go off.
Want to have some semi-harmless fun? Stick a bag of spinach in your luggage next time you go flying. You'll get hauled into secondary for intensive questioning, your luggage will be blown up, and you'll be on the no-fly list. All for a bag of spinach.
Even more fun, put in a big block of cheese.... wiring optional.