A method and apparatus configured to transmit module data between optic modules over a primary communication channel, such as an optic fiber configured to carry network data or outgoing data. The selected material can include a drug, andor the second composition can further include a drug. The electronic shelf label is disposed on a shelf. The subject matter of the invention is also a method for the operation of such a vehicle treatment installation. The shank is biased into the resting position by spring force, which is provided by a spring disk axially supported by the bearing part and having an outer circumference contacting an inside contact surface area of the base surrounding the bearing part. The cut protrusion is measured to determine the flying height of the slider of the head assembly.