Keys made of nickel silver are extremely strong. In fact, nickel silver is one of the strongest materials to make key blanks from, versus keys that are purely made out of brass. Strong, nickel silver keys helps prevent key breakage. Reducing key breakage reduces maintenance and services calls and also helps prevent unnecessary lock-outs due to a key breaking. Language to use in key system specification:The manufacturer will only supply cut keys and key blanks that are constructed of high quality nickel silver.