When running aftermarket management, Speeduino or otherwise on an MX5 usually the factory MAF (Mass airflow) or AFM (Air flow meter) is removed to derestrict the intake.
By doing this the IAT (Inlet air temperature) sensor is removed, this is a key part of any EFI system so one must be added back to the system.
This is usually done by adding a GM or Bosch style IAT sensor somewhere in the inlet runner.
When doing this the common solution is to just jam wires into the factory 7 pin AFM plug or even cut it off and splice into the loom.
This solution is a mating 7 pin plug for the factory connector with 1 meter of wire attached to the IAT pins.
Allowing you to just plug it in and hook up your IAT sensor.
This is designed for the Mk1 1.6 MX5 with the 7 pin MAF