Several additional key pieces of equipment that are provided on most MFL tools:

Odometer Systems. Signals from odometer wheels are used to estimate the location of indications from the start of the inspection or from recognizable features along the pipeline route. Recognizable features include pipeline connections, valves, wall thickness changes at road crossings, and girth welds.

Odometer systems vary in complexity. The simplest systems send a pulse to the data acquisition system every time the wheel makes one complete revolution (the circumference of the wheel is usually a common unit, often 1 foot). More complex systems using optical encoder wheels that send a pulse to trigger the recording of the output of the sensors. Slippage of the odometer wheels on the inside of the pipe affects the accuracy. For this reason, markers that broadcast signals that can be detected by the in-line inspection tool are often placed at known points along the pipeline to create reference points for later signal analyses.

Orientation Measuring Systems. Most MFL tools contain pendulum-type orientation-measuring systems. These systems are used to determine where an indication is located around the circumference of a pipe.

Pressure Containment Systems. All MFL tools provide pressure vessels in which electronic and battery components are mounted. These pressure vessels prevent damage to tool components from the line pressure, harmful gas components, and moisture.

Velocity Control Systems. Variations in velocity during an inspection can significantly affect MFL inspection results, as discussed elsewhere in this report. If induction coils are used, large velocity excursions can lead to difficulties in interpreting the inspection record. Similarly, high velocities lead to decreased axial sensitivity when the data recording rate is independent of speed (at high velocities, fewer recordings are made over a given distance than at lower speeds). Some in-line inspection vendors have tried control systems ^{[Smith92, Naylor98]} to prevent high tool velocities during an inspection with limited success. A number of other systems are under development.

Vibration and Shock Mounting Systems. MFL tools include vibration and shock mounting systems to isolate the electronic components and the battery systems from possibly harmful shock and vibration.