A cartridge secured to either a nozzle andor adaptor unit wherein the nozzle or adaptor unit comprises a substantially annular portion adapted to fit snugly around an end of the cartridge wherein the substantially annular portion acts as a seal against any leakage from the cartridge. To accelerate the currently used method for producing a distributed wave winding the invention provides for a relative indexing to be carried out between the template and coil receiver after a concentric coil group has been ejected and for a further concentric coil group of the same phase with a connection to previous coil group to be wound on the template and ejected in the coil receiver. A reflective element is arranged to rotate about an axis such that the reflective element maintains a constant incidence angle between the optical input and the reflective element for at least a portion of a rotation of the reflective element. An object, placed between the electromagnetic source and the electromagnetic detector is irradiated with electromagnetic energy at the two wavelengths and the electromagnetic energy transmitted through the object is measured by the electromagnetic detector. Accordingly, the number of frequencies can be reduced, and the ping-pong phenomenon can be suppressed.