Leupold / Redfield 182871: 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, each aluminum IMS cantilever design mounts directly to the firearms MIL-spec 1913/Picatinny to raise the scope and push it forward, 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 covered by the Leupold Lifetime Guarantee.