Low-profile gas blocks are increasingly common on modern AR-platform rifles, yet installing gas tubes onto low-profile gas blocks can be challenging because conventional AR front sight bench blocks do not accommodate them.
The new Blackheart International Lo-Pro AR Bench Block solves this problem. The Lo-Pro is the only AR bench block on the market that is cut to accept low-profile gas blocks. Made to work with most low-profile gas block designs, the Lo-Pro is the ideal solution for installing gas tubes onto modern low-profile gas blocks.
The Lo-Pro is CNC-machined from heavy-duty extruded nylon, and is drilled with ambidextrous punch holes for convenient left- or right-hand operation. One side includes the standard rifle bench block profile for use on most semi-automatic rifles, bolt rifles, and pistols. The opposite side features the BHI-exclusive low-profile gas block cutout.
See more: http://www.bhigear.com/bhi-lo-pro-ar-bench-block.aspx