Due to the high voltages involved in secondary ignition systems, it is not possible to make measurements by direct connection, attempting to make a direct connection will almost certainly damage the measuring instrument.

The PP178 is a capacitive pickup which simply connects around the insulation of an ignition circuit component such as a plug wire, this avoids the need for direct connection.

The PP178 comes with a shielded 1.8m (6 foot) lead. It is suitable for use with conventional ignition systems and most HEI and DIS systems.