For the magneto-inductive testing of material properties, the components pass through a feed-through coil. The standard range comprises sensors with round and square cross-sections for a material diameter of 5 mm - 200 mm. The fine feed-through coil increments mean they can be precisely adapted to the material concerned. This guarantees reproducible test results. For a material diameter of greater than 200 mm, we offer customized designs. Even in harsh environments, the feed-through coils operate reliably and consistently.