The 164531-4 part is a thermocouple plug. It is a 4 pin mini thermocouple plug that is designed to measure the temperature in various applications. The plug is compatible with various types of thermocouples, including J, K, T and N types. The plug is designed with a consistent and secure connection ensuring protection against voltage transients. The thermocouple plug is available in standard and special styles, such as straight, right angle, and extended lengths. The 164531-4 part is suitable for a wide range of commercial and industrial applications.