Replaces the standard Glock double stack magazine floor plate (9mm and .40) with a rail adapter so you can attach the MantisX to your firearm if it doesn't have an existing rail. 

Preferred if you don't have a light-accommodating holster and want to train with holster draws.

Compatible with the following models:  

G17, G19, G19X, G22, G23, G24, G25, G26, G27, G28, G31, G32, G33, G34, G35, G37, G38, G39, G44, G45