The TR3K temperature probe is for use with the Maretron TMP100 Temperature Module (optional extra) or the DCM100 DC Monitor (it is included with the DCM100). This probe ends in a ring terminal and can be used to measure battery temperature or any other under-bolt temperature. The temperature range is -4 deg. F to 176 deg. F (-20 deg C to 80 deg C).WARNING: This product can expose you to chemicals including NICKEL (METALLIC) which is known to the State of California to cause cancer. For more information go to P65Warnings.ca.gov. Owner&';s Manual (pdf)