This is an old 30", I think, 3" chamber 1100 barrel. Out is not a vent rib, and does not have replaceable chokes. I still have the original box for thus barrel. I'm looking to trade it for a factory 2 3/4" vent rib barrel for an 1100. This barrel works great on my factory 2 3/4" 1100 with 3" shells, shoots everything I've tried with high brass.