Grip Force Adapter(GFA) is a part that allows shooter to have beavertail for their Glocks. It works much like Glock Gen4's interchanglable grips in its installation. There has been conflicting rumors on whether Glock will produce Gen4 beavertail, but for those of us using the third genration Glocks, this is the best way to go.
Here's the comparison photo between the two versions. Updated version has 4 different changes that seem to reflect customer's feedback.
New on the left, old on the right
First the ridge that was present in earlier version is gone. It was one of features that were discussed on various boards, and I tend to be less happy about it than others. While it gave some supprt for the beavertail and GFA itself, I really didn't see its usefulness outside of that.
(old on the left, new on right)
Second, the height of GFA was reduced. I had no problem with the original height, but the new height also seems to cut just where it needs to be cut.
(new on the left, old on the right)
Third, the edge of GFA seems to be smoothed out. Original version was a bit rough to some shooter's hand, but it seems like when I first grabbed it, it was already taken care of.
(old on the left, new on right)
Fourth, the tang of GFA was redesigned. The original version was just a plain flat surface, but the updated version has more material that is slightly elevated than the first generation as well as leaving smaller cracks for dirt to fall between the grip and GFA.
(old on the left, new on right)
Overall, as soon as these photos were taken, I replaced my old one with new one and I definitely like it better. I haven't had chance to take it out and shoot it, but I think it will work great.