Stainless steel Glock 17 replacement barrel with rainbow, oil slick PVD finish. This is a drop-in replacement component for the Glock 17 pistol and will fit Gen 1-3 slides with no fitting or adjustments. Gen 4 slides will need to use a Gen 3 recoil rod with an adapter. This will not fit a Gen 5. It is advisable to lube the inside, top of the slide to allow the barrel to break in properly as tolerances can be tight at first.