Neutronium is a very dense, very strong metal.  It was invented by the  Zero Agents and is used by them for holding cells, or to block unwanted transmissions.  No known signal can penetrate pure neutronium.
  In the mid 1970s, Doctor Abberant , a rogue Zero Agent, gave the secret to Mr. Clean.   Together, over the course of two years,  Mr.  Clean constructed the largest Neutronium chamber in the known universe.      It is used to hold things that he wishes to keep safe, and or secret.      
   What Mr. Clean has hidden away, hidden from any technological scanner, is known only to him.   It is not known if, upon his death, Mr. Clean gave the secrets of the N Room to anyone.
    To construct Neutronium, one needs first to build a Superluminal Cyclotron.    Doctor Abberant and Mr. Clean built one around the event horizon of a nearby black hole.     The cost in power and raw material to construct  Neutronium is staggering.




Neutronium a jet black, non reflective metal with a structural rating of 100.