PR-12 series probe with chemical-resistant cast iron protection head and screw-on cap includes PT100 ohm platinum RTD element or PT1000 RTD element, 1/2inch NPT mounting threads and sheath of 316 stainless steel. When properly sized, these can go directly into and bottom out in a thermowell. All probes include a screw terminal block for easy connection of insulated copper extension wire. Applications for this probe include installation into large vessels and tanks, as well as large pipes for temperature monitoring.