If you are wondering whether or not this fits your pistol then download the "tri_rail_test_slice" to save you some time and filament. If this 1/2 inch piece fits over your rail and allows your slide to freel move then you should be good to go!
I wanted to deck out my Beretta PX4 Storm with some fancy accessories but it only had the one rail on the bottom. This design slides onto that single bottom rail so that the top slide can freely move while shooting your handgun. This allows for rail mounted optics such as red dots or small scopes.
The addition of 3 rails is nice, but if you would like to have a vertical grip for more support then download the 2.0 file.
I have 2 vertical grips to choose from. the "vertical_grip" is a non moving, basic up and down handle grip. The "pistol_grip" has a pivot in it that fits a 6/32 machine screw so that you can fold it up when not in use.