These chokes are extended, knurled and have a black
oxide finish. they are available in three degrees of full choke- .030, .040,
.050 and were specifically designed for use with steel and other environmentally
friendly shot. this is the ultimate choke for LONG RANGE pass shooting of
waterfowl. All Super Waterfowl chokes are manufactured from a unique grade of
alloy steel that has a strength level of approximately twice that of 17-4. they
are marked on the head with the degree of choke and on the body with the exit
diameter.