Extech SDL200 Four-Channel Thermometer SD Logger 4-Channel datalogging with 6 Thermocouple types (J, K, E, T, R,S) 2-Channel datalogging with RTD (Pt100Ohm) probes Displays [T1, T2, T3, T4] or differential [T1-T2] reading Datalogger date/time stamps and stores readings on an SD card in Excel format for easy transfer to a PC Offset adjustment used for zero function to make relative measurements