Replacement Transmitter For the ET310 Circuit Breaker Finder with Integrated GFCI Outlet Tester, The ET310 Consists of Two Parts: a Transmitter Connected to the Electrical Outlet or Fixture, and a Receiver Used to Scan the Panel to Locate the Correct Breaker, The Transmitter Also Checks for Common Wiring Faults in North American Grounded Electrical Outlets, Transmitter Incorporates a GFCI Tester for Tripping GFCI Devices, The Transmitter May be Connected to Other Electrical Fixtures Using Optional Accessories Which are Sold Separately (Cat. No. 69411), Transmitter is Powered by the Circuit When Connected to the Electrical Outlet or Fixture; No Batteries Needed, CAT II 120V Safety Rating, Built to Withstand a 6.6-Foot (2 m) Drop