We have been using Inductive Sensors in machine projects for several years. In our experience the Chinese Inductive Sensors are great for hobby projects. But for real industry type projects, its not a good solution. The mean time between failure is too low. Also the sensing distance is critical. We have contacted IFM a well known Germany company about these problems. They have a solution, in the form of a high quality inductive proximity switch. A 5 year gurantee is given on the product. The sensing distance is increased to 4mm. Making it easier to detect the end of stroke plates. In all our own project we use IFM sensors. Als we have them integrated in the LSM modules that we sell.