Extech tm300 type k j dual input digital thermometer extech tm300 the extech tm300 type k j dual input digital thermometer provides differential temperature readings while side buttons allow for convenient one hand operation its large backlit lcd shows t1 t2 t1 t2 difference min max and avg supplied with two general purpose type k bead wire temperature probes 3 x aaa batteries and pouch case extech tm300 digital thermometer