If there is a plastic Allen screw on the side of the 123ignition housing, you have the TUNE+ Bluetooth type.

A metal Allen screw indicates either the standard (“Switch”) type or the TUNE USB type.

When you remove the metal Allen screw, you will see either a rotary switch (type: Switch) or a USB port (type: TUNE USB).

If your 123ignition has a blue wire, this means it is suitable for both positive and negative ground (see the wiring diagrams in the manual).

If your 123ignition has short yellow and white wires, this means it is suitable for D-Jetronic fuel injection (also referred to as the -IE version, from Injection Électronique).