Thickness quality control monitoring is better applied on line during the manufacturing process instead of periodic sampling after a product has been manufactured. This way process adjustments can be made "on the fly", reducing or eliminating product that does not meet specification. In some applications, contact methods can be utilized, however, they are slow, can damage the product and are subject to wear. Non-contact sensors are commonly used in these applications.

A typical application consists of two capacitance probes, one on either side of the material being measured. The difference between the output of each sensor is directly related to the thickness of the material being measured. By taking a differential measurement, any positional movement of the material within the probe gap is cancelled.

MTI offers probes for grounded targets using single-ended probes and for ungrounded or poorly grounded targets using push/pull probes.