The REOTEMP Heavy-Duty Windrow Thermometer is specifically designed for temperature readings inside of compost piles and windrows. The clear, easy-to-read dial gives you an accurate reading to +/-1% full scale. The all stainless steel construction is available in both 5/16" or 1/4" diameter stem, but for heavy-duty composting, the 5/16" is recommended. The Heavy-Duty Probe also comes standard with a hermetically sealed head and plastic lens.