The Murphy 518PH-12 Tattletale allows for Swichgage and/or N.C. contacts to be wired "Closed Loop" (in series). Any contact open or Swichgage contact close in the circuit shunt trips the 518PH-12. The 518PH-12 is a 12 volt model which features a manual indicating reset type. The control circuit output contact is NCH. In the latched position the NCH contact has a "hot" output. The latch type is energize to latch. Contacts are rated for 10 amps 12V. A 14 amp fuse is included. Use for distributor ignition or diesel engines.