The Topworx part number 35-13319M is distributed by Electrol. The product that you are looking to replace may be brand labeled GO Switch, Topworx, Valvetop or Emerson. Topworx is a division of Emerson and headquartered in Louisville Kentucky. Products include discrete valve controllers, proprietary technology GO Switch brand proximity and non contact limit switches. We have both nuclear approved and subsea products for the harshest of environments. Focus industries are oil & gas, pulp & paper, grain handling, food processing, power generation and waste water treatment. Electrol has been an authorized distributor of Emerson Topworx since 2011.