The 51864 is PIDG series Fork/Spade Tongue Terminal designed for uniform reliability in the most difficult circuit environments. They consist of a tin-plated copper or tin-plated phosphor bronze body for spring spades, plus a copper and coloured insulation sleeve fitted over a terminal barrel. The specialized design of tool dies and the construction of the terminal allows for uniform insulation thickness under crimping pressure, transmitting this pressure evenly to the centre of the crimping area. The body has serrations for maximum contact and tensile strength. The insulation sleeves and the corresponding tooling are colour-coded by wire-size for easier identification.