This 12V Cole-Hersee max 85A continuous master relay is provided with an already prepared diode to protect your switches from collapsing fields (the biggest knock on effect from these wonderful bits of kit). The master relay is 'triggered to ground' by the master switch in the cockpit (not included), which then activates the relay to hold power between the battery and the airframe. This requires little current and ensures that large amounts of current are NOT travelling through the master switch in the cockpit. However, without the diode fitted you may experience early failure of the master switch due to 'collapsing field' current reversals and in-switch arcing that are common on all relays. Note, the diode is mounted with a long lead to be able to enter the boot on the battery side connector.
Housing : STEEL
Bracket mounting holes: 5/16" x 19/32" on 2 13/64" centres
Contacts : Copper
Tickler 10-32 stud (torque to max 15in/lb)
+ve terminals 5/16-24 Studs (torque to max 35 in/lbs)
Image for illustrative purposes only