Intended use is for attachment of a mono pod shooting stabalizer on the Boyds At-One Stock. It is a one to one modular component that will exchange with a standard bottom cap.Dimensionally the same as the standard bottom cap with a 3 slot section of picatinny rail built in. Designed so the rail section is parrallel to the bore. It is machined out of one piece aluminum with black anodization. Remove the standard bottom cap and install new bottom cap with rail section.