When building or performing maintenance on AR-15 carbines, there are some elements of the lower receiver that require the proverbial "third hand" to complete, frustrating first-time and experienced AR aficionados alike. With this Magazine Well Vise Block, now you have your third hand! Each AR-15 Magazine Well Vise Block can be clamped into a user's workbench vise, allowing users to insert their lower receiver onto the exposed section of the block for a solid, secure working point. The block itself is made from injection-molded polymer and is made in the USA. The unit is designed for use with mil-spec AR-15/M16 lower receivers only.