The Delta Series LR308 Mag Well Vise Block is designed for use with the TiptonA(R) Best Gun ViseTM but can also be mounted directly to a workbench. Simply inserts into the magazine well and provides a steady base for cleaning or light gunsmithing on your LR 308, in either breech or closed position. Easily installs into the aluminum track on the Tipton Best Gun Vise. Loaded with handy features, this tool is a must have for anyone with an LR 308. See below for compatibilities. Bench top mounting fasteners and Best Gun Vise fasteners are included. Compatible with all "LR" style lowers which use the SR25 type magazines