When you say very accurate, how accurate do you mean? I have one with a (now expired) NIST-traceable infrared calibration certificate performed by using black-body calibration sources with defined emissivities. Cost $750 new, then $125 + shipping for each yearly re-certification mapping. It was used in a food processing plant. The $25-$75 cheapies side by side mapped within 10% of the 'good' one, but of course wouldn't satisfy the inspectors. You get what you pay for.