All brass & steel construction, variety of colors and finishes & tungsten carbide ballpoint tip | The 400 series bullet space pen is the original Fisher ball point pen & most popular Fisher pen sold | Each Fisher Space Pen is precision assembled, hand tested, and carries a lifetime guarantee against all manufacturing defects | Reliably performs in extreme temperatures (-30F to +250F), underwater, in zero gravity, at any angle | Precision assembled & hand-tested with a lifetime guarantee against all manufacturing defects