i just picked up this contraption at a garage sale a week ago and the lady said it was something that her husband owned for scuba diving. I found a instruction manual in the holster and it says it is a "underwater defensive weapon" It has no company name on it. it is a green aluminum two piece connected by a short piece of braided wire at a point were it clips together to make about a 2 foot stick. it has a spring in it and a place were the cartridge goes in. the directions don't say what kind of cartridge it fits either. if anyone knows who makes these or any info on it please let me know. thanks