this is a 12 ga "open " choke tube to fit beretta/Benelli mobli -choke barrels "Carlson's Tactical Breecher Choke Tubes allow you to turn you adjustable choke system barrels into a aggressive looking home defense gun. The open choke allows for shooting with lead, buckshot, Hevi-Shot, or Steel shotshells. You can rely on this choke tube for your security needs. The Tactical Breecher choke, like all other Carlson choke tube is backed by Carlson's lifetime warranty.
Fits:
Barrel Threaded for Standard Beretta/Benelli Mobil Chokes"

David, this is an "Open Choke" so there are no restrictions on ammo usage. You can verify this with Carlsons under "TACTICAL BREECHER CHOKE TUBE" here (just scroll down) : choketube.com/customer-service-details-R.php?Choke-Tube-Information-3

This is a 'full' or "extra Full" diameter. (.700") No slugs. Designed for shot use (blowing doors open).