This is a drop-in replacement rail for the Accuracy International AT rifle, precision machined from 7075-t6 alloy and class III hard anodized. The rail is nearly half the height of the original while maintining minimum Picatinny Spec for lowest possible mounting. It is also shorter in length at 5.6 inches to allow more flexible mounting of the more modern shorter length scopes. EuroOptic AI AT 20 MOA Low Profile Scope Rail (Mounting Hardware Not Included)