Great little addition to any AR15 Build.  This little guy helps when you need to change a mag FAST and your hand isn’t fast enough to eject.  Adding length can make it so the slightest touch with the hand and the magazine ejects. CAREFUL, if you push really hard, you can push the mag catch out the other side.   Comes in a variety of colors.  Installs same as your standard Mag Catch button.