The HHA TWI01 Tactical Writing Instrument features a dome shaped crown constructed from high grade stainless steel that can be used as a striking point in an emergency situation or o break glass. At the other end they incorporated a pointed tip for investigative type work or for use as a PDA stylus. The entire shaft of the pen is constructed from 6000 series, non-reflective, Black anodized aluminium for extreme longevity and wearability. The TWI01 incorporates a series of O-rings making it completely waterproof when the pen cap is screwed down over the writing tip. It will accept standard Parker and Fisher Space Pen refills.