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Page 1 Model 421508 Version 1.0 October 2002
INSTRUCTION MANUAL
Model 421508
Dual Input, 3-Display Handheld Thermometer
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Accepts J, K, T, E, R, S, & N thermocouples
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Backlit Electro-luminescent LCD Display
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T1 / T2 / T1 – T2 displays
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MIN / MAX / AVG Record/Recall
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Selectable temperature units (C/F)
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Data Hold, Relative Mode, Elapsed Timer
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Bi-directional RS-232 PC Interface
Introduction
Congratulations on your purchase of Extech’s Dual Input, 3-Display, Hand-Held Digital
Thermometer. This portable digital thermometer is designed to use external K / J / T / E / R
/ S / N type thermocouples (K-type supplied). Temperature indication follows Reference
Temperature/Voltage Tables (N.I.S.T. Monograph 175 Revised to ITS-90). This
professional meter, with proper care, will provide years of safe reliable service.