This durable, multi-purpose and essential tool clamps into a bench vise, so that you can then slide a .308 lower receiver magazine well down onto the upper portion. It is designed to work with .308 lower receivers that accept SR25/DPMS style magazines, and provides a stable platform to perform a variety of repairs or installations. CNC cut NO-MAR® polymer construction protects your receiver’s finish. Multi-Lock® feature locks receiver in any position – install through top or bottom of Magazine Well. Works with the Upper Receiver installed or removed, and provides access to trigger guard, pistol grip & buffer tube to make trigger & safety installations much easier. Works in any size bench vise, and the machined support lip avoids any strain on your magazine release. Made in USA.