NITECORE NTP31 is a uniquely designed aluminum alloy bolt action tactical pen. The three position bidirectional bolt action allows you to pop out the pen tip or windows breaker, or retract both for everyday carry. The NTP31 houses an easily replaceable Schneider gel ink refill for quick drying, waterproof, and fade resistant writing. On the other end of the NTP31 is a tapered tungsten steel point window breaker, whose hardness is only second to diamonds.