This Leupold Mark 4 IMS Base delivers rock solid dependability when you demand it most. The Mark 4 IMS Integral Base from Leupold can be used with the 30mm Integral Ring insert, 20-MOA Integral insert, or 1" Integral Ring insert. The Leupold Mark 4 Base allows a comfortable and accurate way to mount scopes to your AR style rifle, giving the optimal height and eye relief. Leupold mounts are designed for maximum strength, performance, and versatility for your shooting and hunting needs. Whether you are looking for an AR base, AR mounts or mounts for any number of firearms, you can be sure you will have a quality experience every time.