Bought a Mag Extension (rem I think) with male threads where it fits the other male threads on the factory magazine tube.....I need an adapter of some kind.....can any one help.....Hal...this is for a Rem 870 12 Ga.

I have to agree with you on that one, I have never seen a rem 870 with a male threaded extension tube. Mine is fitted with a TacStar 7+1 tube, and it (the extension) comes all in one piece(female threaded) except the extended spring.
...However! there are two dents in the original magtube, wich are ment to guide the plastic springholder(wich in turn is ment to hold the spring down when you unscrew the magtube nut, so that the spring doesn�t shoot away when the magtube is dismounted) You have to take away those two dents if you are fitting an extended magtube (otherwise the cartridge follower won�t go all the way up into the mag extension). Just take a drill big enough to take away all of the dents and be sure to file the inside of the holes so that rounds and spring doesn�t snag the edges of the holes.
...As for the extension with a male thread... toss it and buy a good one, it�ll save you a lot of time and trouble and the gun will function better!