Charles Bosse January 13, 2011 04:35 PM Great. A knife capable of misfire and blowback. Just what we need. Rex Alfie Lee January 21, 2011 02:47 AM Perfect! Now criminals who can\'t use guns in Australia may get one of these which will though not legal, be unnoticed when someone comes in to a bar-fight & kills someone with an explosive blast... Michael Mantion May 24, 2011 04:11 AM Sorry rex, criminals use guns regardless of the laws... They are criminals, by definition, it means they don\'t obey the law.. Although I think this is truely a stupid knife, Id pay them $1000 USD if they jump into the water with a shark, stab it and then push the button. it would take way too much force to get any serious penetration in a still animal. let alone one that moves as fast as a shark in water.. If you did get it in you would have a micro second to push the button. By the time the shark would react he would of most likely taken a fatal bite from you, and soon his friends will come to finish things. I assume all the same would apply with elephants or bear. I do think that the noise the device produces might deter the animals.. That said I am sure there are $10 devices that are capable of the same. alcalde July 23, 2011 07:48 PM What seems to not be taken into consideration in this design is Newton\'s law \"for every action there is an equal and opposite reaction\". If the knife is expelling gas at 850psi, you\'re going to have the knife attempting to move in the opposite direction with equal force. Most likely the knife is going to, as Mr. Bosse rightly imagined, shoot out straight at the user, probably before delivering most of its content. Francis Rocanella August 17, 2011 04:07 AM it needs a gripping blade, like an arrowhead. that COULD get rid of the blowback idea. but its only a chance if you got the knife deep enough Andrew Yang August 17, 2011 09:10 AM @Michael Mantion True, but you forgot about the fact that the gas is not expelled out of the tip of the knife, it is expelled on an angle, thus reducing the blowback force. http://www.youtube.com/watch?v=Sa_NC-_fvKs Sara Durocher August 24, 2011 01:12 PM I think this is a handy invention for the outdoor inthusiast. For a bit of piece of mind while hiking, hunting or search and rescue groups that are in wooded areas. As much as I never want to be that close to an animal, things happen and I would rather be prepared with SOMETHING rather than nothing. Even bear/pepper spray has to be used in close proximity, so maybe between the 2, a person will have a chance. I would consider buying one. Ron Wagner September 19, 2011 04:23 PM Very ingenious, and very scary. Just about any weapon whatsoever is illegal in Illinois, where I live however. I imagine this will be added to the list. Of course that will not stop most criminals. We are trying to get concealed carry passed. Illinois is ruled over by the Chicago machine. Maybe not after 2012 however. steve1968 September 30, 2011 02:55 AM \"Perfect! Now criminals who can\'t use guns in Australia may get one of these which will though not legal, be unnoticed when someone comes in to a bar-fight & kills someone with an explosive blast... comment Rex Alfie Lee - January 20, 2011 @ 09:47 pm PST\"Well Rick that just goes to demonstrate the complete and utter stupidity of trying to control criminals by banning inanimate objects. You don\'t stop criminals you just take away your best tool for defending yourself against them. Of course you don\'t ban knives, gasoline, motor vehicles, golf clubs or numerous other things which someone can use to kill you in short order either. Jim Parker October 7, 2011 02:35 PM \"Well Rick that just goes to demonstrate the complete and utter stupidity of trying to control criminals by banning inanimate objects.\"Well Steve, then why not allow people to carry any weapon they please? In bars? On airplanes? Don\'t mind the guy with that bazooka, he\'s just asserting his holy Second Amendment right to carry WMD\'s around the shopping mall.As any gun-head knows, the Holy Second Amendment was intended by the Framers to outweigh any other rights their victims might be foolish enough to think they have. That\'s why your holy right to carry an Uzi into a bar (don\'t forget those hi-cap clips), is even more important than your right to push your religion on other people\'s kids.If you really want to get a handle on complete and utter stupidity, try examining the real-world consequences of lifting all bans on personal weapons. Blood, screams, trials, prison, funerals and PTSD nightmares: That\'s what\'s missing from your video games!