The operating environment of a capacitive proximity sensor can greatly narrow the selection options. Exposure to oils, chemicals, washdown conditions, noise, or presence of hazardous materials might require specialized sensor capabilities. Some capacitive sensors even have built-in humidity or dirt compensation to increase uptime and reliable performance. Common capacitive sensor body materials are polymers such as ABS, PA, PBT, PP, PTFE, PVC, or metals such as aluminum, brass, nickel-plated brass, or stainless steel. Metal housings are durable and beneficial if potential contact with the sensor could occur. Polymers are preferred if there is potential exposure to specific chemicals. The minimum and maximum temperatures the sensor will experience during operation and storage must be considered. Some capacitive sensors have an increased operating temperature just for the sensor face.