The patented construction of this incredible choke slows the wad and ensures the tightest, most consistent patterns we've ever seen. Our tests with large steel shot and buckshot convinced us that these tubes outperform every other tube on the market. Consistent patterns of 100% in 20" at 40 yards with 3" mag. 00 buck is the kind of performance we experienced. These chokes use a combination of controlled constriction, internal lugs and venting to achieve superior pattern control. The controlled constriction takes place in the beginning two-thirds of the choke tube. The internal lugs then engage the wad as it passes through the choke - slowing down the wad - the ports (venting) allow the gasses to escape without blowing the shot cup through the shot pattern. The result is an enhanced shot retention in the center of the pattern. If you want tight, consistent patterns, try one of these. You won't be disappointed.