Using an inductive head, GLS (Gap Level Sensors) measure the metal level in the molds. The sensors allow continuous monitoring of metal level changes during all stages of the casting process. The inductive technology we master has no interference with smoke or metal surface condition, resulting in very robust measurements due to the ease of zeroing. This sensor is completely unaffected by grease or smoke deposits, reducing the need for regular maintenance. The standard period of use is up to one year without the need for maintenance. In addition, the special design of the head is very tolerant of the proximity of other devices, which allows for a very compact installation and reliable, repeatable and accurate measurements. Two models are available: the U40 and the U15. The GLS U40 is suitable for ingots. The GLS U15 was developed for large rectangular and round billets (diameter > 500 mm). Both sensors are supported for the next 10 years because they are built with the latest electronic components. The shutters are driven by the GLA (GAP Level Actuator) which controls the flow of liquid metal. The GLA is a reliable and very robust instrument to safely regulate the metal flow, especially in case of an emergency stop or power failure. GLAs are direct drive actuators to achieve more precise movement of the rod relative to the nozzle and to limit operator intervention. The system can be supplied with a clamping or centering capability for even more precise adjustment of the spindle to the constraints of the runner.