by extended i mean tubes that extend beyond the muzzle of the barrel.
when it comes to aftermarket tubes, i am a big fan of briley's extended tubes.
only the new benellis (SBEII, M2, ect) have the new crio systems and yes they have been lengthened inside the muzzle so it is a similar consept. there are also exteneded tubes for the crio systems which, in theory, would produce even better patterns with steel but yet to see any tests.
hope it helps