Limit Switch are basic switches that have been encased to protect them from external forces, water, oil, and dirt. Many models are available, such as those resistant to head, cold, or corrosion, as well as high-precision models. A wide variety of Switches are available including environment-resistant models that are compact, thin, and durable, two-circuit models with spatter countermeasures, and four-circuit models with bifurcated contacts and a block-mounting system.