It is included with the package Cylinder to simplify your life. It is possible for proximity sensors to function well at -25°C~70°C. A 2 pin electronic component is used here. Proximity sensors should have their supply voltage set to 24V for maximum effectiveness. For DC circuits, proximity sensors can handle voltages as high as 30V without causing damage. There shouldn't be a current lower than 10V in the DC circuit of proximity sensors. A nominal supply current of 13mA will ensure normal operation of the proximity sensors.