Lampholder, SVCE (642, 680, 690, 561)
600 Serie Use Prior to Serial #2054736.
          Starting With #2054736 See 3050230.
  561     Use From Serial #1810000 to 2054736.
          Prior to Serial #1810000 See 3050010
          or 3010070.
          Starting With #2054736 See 3050230.