Specifications

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temperature measurement productstemperature measurement
RTD Probes
The Techne model WSP425 and SSP660 PRTs are an excellent choice for use as reference sensors
in all types of systems, including dry block calibrators, liquid calibration baths, ovens, reactors and
other applications where temperature needs to be accurately measured.
Our PRTs o er proven and reliable performance for critical temperature measurements. They can
be used with our Tecal Accu-Temp indicator or any comparable unit. Both models include a carrying
case and ITS-90 calibration (NIST traceable) certi cate with coe cients and resistance vs.
temperature table. The SSP660 has excellent performance, speci cations and wide temperature
range at an a ordable price, while the WSP425 is designed for measurements within a narrower
temperature range.
The model WSP425 has a calibrated operating range of -50 to +425ºC, and the model SSP660 from
-80 to +660ºC.
425ºC Working Standard PRT
The model WSP425 PRT is a great choice when lower temperature range is required.
The sheath is of stainless steel construction with a strain free wire wound .3924 alpha sensing
element.
The WSP425 PRT can be used as a working standard in calibration baths, furnaces,  uidized baths,
dry block calibrators or for any other temperature calibration work.
Combine it with our model Tecal Accu-Temp RTD indicator for a system with high overall accuracy.
The WSP425 PRT includes a NIST traceable ITS-90 calibration with coe cients and R vs T table.
Technical Speci cations
Resistance at 0° C: 100 ohms
Temperature range: -200 to 425°C
Calibrated temperature range: -50 to 425°C
Temperature coe cient: 0.003924 Ω /Ω /° C minimum
Stability: Meets IEC stability speci cations after 250 hours exposure
to extremes of temperature range. Typical drift is less than
0.05°C (0.02Ω) at 0°C.
Repeatability: Meets IEC requirements. Typical shift less than 0.05°C
(0.02Ω) at 0°C after ten cycles over range.
Dimensions: 0.25” dia. x 12” L , custom sizes available
Tolerance at 0° C: ± 0.06%, IEC DIN class A
Lead wires: 4 wire Te on insulated, stranded 22 AGW copper x 6” Long
Calibration
Each WSP425 PRT includes an ITS-90 NIST traceable calibration with a+, b+, a- and b-
coe cients and R vs T table. A padded carrying case is also included.
Calibrated uncertainty (K=2)
-50°C ±0.040°C
-20°C ±0.035°C
0°C ±0.030°C
230°C ±0.035°C
420°C ±0.050°C
(Calibrations down to -196°C available upon request.)
Ordering Information
7002617 425°C Working Std 1/4” PRT with carrying case