The standard 9mm 90 Series full size threaded barrel is made of a special blend of carbon steel to ensure durability and safety in the open to slide design of the Beretta 90 Series Pistols. They are extended past the typical 92FS barrel length so that items threaded on have enough clearance and engagement to safely and properly function. These barrels are 5" in length, are assembled with the gen 3 locking block and a thread protector and O-ring.