Breaker Strip,Fre Mullion SVCE (611, 511)
  611     Use Prior to Serial Number 1810000.
          After Serial #1810000 No Breaker Strips
  511     Use Starting With #1004775 And Between
          #964470-964769.
          Prior to Serial #1004775 Except Between
          #964470-964769 See 7021991.