Real avid vise block - Real Avid Smart-Fit AR15 Vise Block

For the price you really can't beat this vise block. It's the only block out there that adjusts to magwells and securely fits without any wiggle room. The block is made of very solid and robust plastic, but it feels like there's a metal core. It's very very solid. The red knob at the bottom is easily adjustable to move an internal pin up or down thereby spreading the upper "flaps" outward to fit in any magwell. With this securely inside your ARs well, there is absolutely no budging or play whatsoever. It has made armoring work super simple. I would say this is by far the best AR vise block on the market today and I highly recommend it. For the price it beats Magpul's block by far.