The lugs are secured closed by a salt-blued or parkerized and knurled carbon steel ferrule. Press fit inserts are internally threaded and have a knurled outer diameter. The knurled surfaces provide enough grip to hold the nut between the thumb and forefinger. A knurled nut is a nut with a knurled outside surface. A small, knurled nut threads onto the barrel to protect the threading. Finally, the flagship pen, the 701 has a knurled grip and is completely stainless steel. The one-piece striker terminated in a Springfield-like knurled cocking-piece. Most are available with a knurled aluminium body, similar to Swiss Army knives. The telescope is focused by turning the knurled focusing sleeve. It is a thin knurled ring, usually located in front of the Focusing ring. They usually have knurled heads so they can be easily removed. ISO standard for Knurled cup point set screw is ISO 4029. Knurled nuts are typically used in electrical components, musical instruments and in automobiles.