Use models with Type 4 (NEMA) enclosures for indoor or outdoor applications in high humidity environments. Use these models with pipes that carry fluids at temperatures in the range of -20°F to 250°F (-29°C to 121°C). A sealing O-ring between the cover and case facilitates you to use these models in high humidity environments, or applications where the fluid temperature is below the ambient dew point temperature. Do not use these models in applications or environments where the temperature may cause the fluid to freeze.