And a Havoc stand alone, they also make a Spikes 26.5 flare launcher that uses a AR lower if you all ready have a few kicking around. H.K make a pistol type as well.
Inserts are to available to chamber 12 gauge, 410, and many others, but it they becomes a DD (Destructive Device) and I would never have that on board on a deserted cove on the back side of some island.
Cheers, Don
You would be much better off with a stainless mini 14 or marine 12 gauge and a flare gun. JMHO. But the spikes flares are cool.