The ABS interface takes the signal produced by an ABS Wheel Speed Sensor and converts it into a format that can be used to operate a Monit rally computer. It will work with most types of two wire sensors that generate an analogue output signal
Note:
The interface can only be used with ABS wheel speed sensors that have been disconnected and are no longer used by the vehicle’s safety systems. It must not be fitted to any vehicle that still uses its ABS system.
More detail see