SP Stainless Plate Temperature Sensor Must be used with Refrigerator/Freezer Guard. The SP is the best temperature sensor for walk-in coolers and open display cases. The stainless steel plate creates a shield over the sensor. Mounted easily to a wall. Each temperature sensor incorporates a Class A, Thin Film Platinum RTD sensor which conforms to DIN-IEC-751 platinum RTD standards. Sensors are available in two or three wire configurations specify in comments section of your order , incorporating high accuracy and interchangeability throughout a wide operating temperature range. RTD stands for Resistance Temperature Detectors. RTD sensors measure temperature by correlating the resistance of the RTD element with temperature. Platinum is the material of choice for RTD sensors platinum has the most stable resistance-temperature relationship over the largest temperature range SP Temperature Sensor Specifications NIST certificates are available for an additional charge. 2 of wire included with each sensor, more available for purchase Designed to be mounted in a standard 1-Gang switch box. For models, VM505E, VM505, M303, M304, M305, MA412, CM712 Output 1K Ohms 32 degrees F 0 degrees C Accuracy /- 0.06% 32 degrees F 0 degrees C Single Point /- 1.0 Ohm 70 degrees F Averaging Stability Less than /- 0.1 degrees C drift Repeatability /- 0.2 degrees C /- 0.36 degrees F Operating Temperature Range 58 to 392 degrees F 50 to 200 degrees C Temperature Coefficient 0.00385 Ohm/Ohm/ degrees C Standardization DIN-IEC-751 formerly DIN 43760 Resistance Characteristics /- 0.06% Class A Standard This item ships from a separate warehouse and may require extra time for delivery.