We used the extension for a Kel Tec PF-9. Fits on the Taurus mags like it was made for it. Just slip off the Taurus floor plate and slip on the Kel Tec one. The extension costs about $10 each. Here is a pic:
I know it kind of looks funky, but it works great. The no problem with functionality of the weapon. We put one on both magazines. The way it kind of sits back gives both my wife and something to wrap our pinky around. It does not add anything to the print of the weapon for concealed carry. My wife carries it at 3 o'clock in a Kholster IWB rig. I have carried it a couple of times as well.