HELP! MAGAZINE EXTENSION

[Tonino90]

Hello, I have a Remington 870 express for H.D.
I would like to install a +2 or a +3 magazine extension (I am aware that they are the same aesthetically, I like that the extension ends equally in the upper 18 "barrel). Unfortunately I cannot find any for sale from the remington brand and that it can be shipped to Italy .. do you know a site where you can buy it? then what color should I take to be the same as the upper barrel (parkized or blue?)

[Fordtruckfan89]

When remington was bought out, the factory parts/ accessories became basically unavailable. Ebay has some, but they are marked way up. I'm going aftermarket, since there's no telling how long it'll be until they are available again.