Mark 4 IMS 30mm 20-MOA Matte by Leupold Optics The Leupold Integral Mounting Systems (IMS) family quickly and easily eliminates the two most common issues faced when mounting standard riflescopes to AR-style rifles; scope height and eye relief. From the Mark 1™ to the Mark 4® and each aluminum IMS cantilever design mounts directly to the firearm’s Mil-Spec 1913/Picatinny to raise the scope and push it forward and eliminating the need for risers or specialized optics with shortened eye relief. All Leupold IMS products are tested to endure the rigors of the field and are covered by the Leupold Full Lifetime Guarantee.