X15T.N is used by several knife makers (Boker, Cold Steel) for usage requiring extreme corrosion resistance. Boker uses it on a premium dive knife. Boker says this about it:
Through rigorous testing by the German GSG-9 elite forces, the ORCA dive knife held up even under the extremely corrosive effects of seawater and performed so well that it is being considered as an official standard issue knife of the German GSG-9.
Benchmade says this about it:
X15 T.N- This steel was developed for the aircraft industry for jet ball bearings, as well as the medical industry for scalpels. It has the ability to resist rust in the worst of conditions while maintaining ample edge retention. The capability behind this steel is in the way it is manufactured, resulting in the finest steel for use in harsh environments such as salt water. The edge on an X-15 T.N blade is easier to maintain.
