My only complaint on the is that as an extended magazine it should also extend the pistols grip. Without that it gets pulled back by your ring and pinkie fingers when gripping the pistol. This causes the magazine to be pushed towards the back of the gun, putting stress on both it and the magazine release. Also, whats up with the butt-plate ? The magazine extends far below where you would be able to use the finger extension.
That being said, this magazine works very well in my LCP, and having the extra rounds available is nice. I Just wish they had done their homework on this extended magazine like Pro Mag typically does.