The base is very well-made and well-finished and fitted perfectly onto the Merkel rib, just forward of the reciever. It came with four flat-topped Torx screws for fitting the Micro sight to the base and a proprietary Aimpoint Torx driver. Surprisingly, this was not the correct size for the screws, The base mounts very solidly to the rifle and the Micro sight fitted the base perfectly. A very good product which would have been perfect had the Torx driver fitted the screws.