This is a XS Sights Mount known as the Picatinny, model ML-6000R-N.
The XS Lever Scout Mount allows a scope or red dot sight to be mounted in the forward" scout rifle position. Fits Marlin 1895 with round barrel" .45-70" .450" or .444. The rail is machined to Picatinny specs from a lightweight aluminum. Requires removal of factory rear sight. Rail mounts to forward receiving holes and rear sight dovetail with a pillar assembly. All screws torque to 20 INCH-pounds; over-torqueing can fracture or break screws.
Features:
Aluminum construction
20 inch-pound torque specs