No special tools needed. Just press inward on the round button in the center of the original base pad and slowly slide the base forward about a quarter of an inch. Put your thumb over the end of the mag and cover the bottom of the mag as you slowly slide the original base pad off. Be sure you keep constant pressure on the bottom of the mag as you slide off the base pad. You are trying to cover the exposed bottom of the mag opening so that the spring does not come flying out. Now while holding down the mag insides with your thumb you start to slide on the mag extension while slowly backing up your thumb from the opening. Continue to slide on the extension until the button clicks into place on the new base. They come with a replacement spring plate. You can use this for a better fit.