The Weaver 2-Piece Grand Slam Steel Dovetail Base is constructed with an eye on durability and strength providing you a piece that will last a lifetime. These bases are comprised of steel and able to withstand heavy use and recoil. The mounting system comes in two pieces for better adjustment and features the locking dovetail system to ensure you have the most secure fit on your locking rings. You will find the alignment on your scope will hold up longer with this stable mount.