Backstrap addition is held in place by hooking into the bottom of the frame, snapping into the groves on both side of the backstrap and then secured at the top with the frame pin.
New recoil spring assembly. It will not fit the Gen 3 and older versions.
Fuzzy pic looking down in the mag well. I'll get a better pic soon.
"MBS" molded into the right side of the frame.
The reaction to this pistol has been nearly 100% positive. Most people really like the feel of the new RTF III frame and love the new mag release.