Strike Industries 16" carbine barrel extnesion

[hholman]

Do any of you guys have familiarity with Strike Industries' 6" carbine barrel extension? Are they even legal for use in CA?
I saw S.I. advertise on one of the sponsored link at the top of this site. Also, here is the link for the product I'm talking about on Amazon:

http://www.amazon.com/SI-COBRADB16C-16-Carbine-Barrel-Extension/dp/B007KD77X8/ref=cm_cd_pdp?_encoding=UTF8&cdPage=1&newContentID=Tx2HN19PKV1ZWB4&noLL=1#CustomerDiscussions

Part of the product description says: "removing the front cap, you can install any AR threaded compensator to reduce muzzle flash and recoil, thus enabling you to have your cake and eat it too."
It looks & sounds cool, but I was under the impression that you have to have uppers fixed/neutered with flash suppressors permanently attached to the barrel. Any truth to that?

[duc748bip]

It's legal and heavy as a fake can because it's solid block of aluminum. They are making a line of comp to the same outside diameter of the fake cans so you can have a muzzle brake on top of the fake can, and still look kind of decent.

[IntoForever]

It's legal if permanently mounted and brings the total barrel length to over 16". On a barrel length over 16" it shouldn't be a problem unless you forget to tighten it down.