Rem 700 Long Action Bar Night Vision Rail Step Down.  This base is constructed of T-6 7075 hard coated black anodized aluminum with a full 1913 rail. Base is 16" long and comes with #8-40 screws for mounting base (these screws will require most receivers to be drilled out from a #6 screw.)  The base has side rail mounting holes for adding side rails in the future (not included). Weighs 10.4 ounces.  Rear elevation is .740" and there is .280" of drop from rear to front rail.