A magazine-well vise block for AR-15 / M4 mil-spec lower receivers. The block slides into the lower's magwell and gives you a flat surface to clamp in a bench vise, holding the receiver steady while you install a lower parts kit, buffer tube, grip, or trigger group.

Features:

• Magazine-well insert for bench-vise clamping
• Fits AR-15 / M4 mil-spec lower magwells
• Stabilizes the lower for lower parts kit and buffer-tube assembly
• Compact — sits flat in any standard 4" bench vise

Compatibility: Mil-spec AR-15 / M4 lower receivers only. This block holds the LOWER receiver only — for barrel-nut torque and other upper-receiver work, use a dedicated upper-receiver vise block or upper reaction rod instead. Confirm your lower's magwell is not proprietary (some non-standard lowers use a different magazine cut) before use.