If you pick up the 20 gauge Home Defense model it comes with an 18" barrel and 2rd extension.
if the 20ga mag extensions are anything like their 12ga counterparts, id recommend the Scattergun Tech ones -- theyre quite well-made. where are you finding them though? Brownells only seems to have the Choate mag extensions in 20ga - which IMO are pretty crappy mag extensions and should be avoided if possible (plastic end cap, seams on the inside that need to be honed away, binding, etc).Both Remington and Scattergun Tech make 20 gauge extensions.
Looks like they may have changed the name to "Express Synthetic 7 shot". Kind of rolls off the tongue doesn't it?It's too bad that no one makes a short barrel (14") for a 20 gauge.
Tried to insert an image but I'm having problems, here's a link instead. Model No. 81100 for the 20 ga.
http://http://www.remington.com/products/firearms/shotguns/model-870/model-870-express-synthetic-7-round.aspx
I've never bought a two round extension from Scattergun Tech but Wilson Combat does list them, part No. SGET-RH-2-20



























