Donald, this Security shotgun comes with a Cylinder Choke Sir. ***NOTE*** It is the The 320 Turkey that comes with an extended extra full turkey choke, not this Security model. It takes Winchester Win Chokes. Cheers and stay safe!

it incudes a cyl choke. The Stevens 320: interchanges with Trulock’s Win win choke-Brn invector-Moss accu choke style.https://trulockchokes.com/choke_interchange_list.html

Comes with Extended Extra Full Choke Tube ( takes Win. Choke)
As detailed here, (talks about the chokes at the very bottom of the article.)
thetruthaboutguns.com/savages-new-stevens-320-thumbhole-pump-hunting-and-defensive-shotguns/

This has a cylinder choke. I recommend contacting Savage customer service ( savagearms.com/content?p=contact ) to see what Choke fit it, there's very little information out there.