I found a "Mares Frontiersman" speargun at a pawnshop for $40. I know NOTHING about spearguns except the little I've read and am about to watch on Youtube. I just found it today. There's a serial number on it, guessing I'll check to see what info I can get from it. Anyway, I guess it's kind of old? The salesman said that he was new there, but that at some point it would have had to have been tested if not the manager would have not accepted it (someone lost it in a loan). Any way, it has a string on it, attached to the main tube and the spear, too short for any spearing underwater in my opinion, but what do I know. So what do you guys think, from the almost non existent info I just gave, lol. But seriously, if I were to, give it a tune up, what would I look at replacing? O-rings, fittings, etc? Any info you all can share will be very much appreciated. Thnx. Off to do some research!