Via The Shooting Wire and His Most Trenchant Codgerliness, Jim Shepherd:
"...Having run a few hundred rounds into -and absolutely none through- the test unit I was provided, there are a couple of observations I can make with absolute certainty: 1) portable doesn't mean "man portable" and 2) it absolutely does exactly what is promised- it traps bullets.
That's made possible through the use of a five-high stack of patented Dura-Bloc ballistic rubber. The Dura-Block captures rounds with a minimum velocity of 600fps all the way up to 308/7.62. The blocks are large enough to be engaged by the average shooter at virtually any range. It's 24"x45" size makes it pretty simple to put rounds into the big black blocks. The Dura-Bloc panels, in turn, absorb those rounds without three big concerns when you're shooting: ricochet, spatter and lead dust...."