Tempilstik 028105 Surface Temperature Indicator, 500 degrees F (One Indicator) Accurate results are +/- 1% of rated temperature; Reliable always in calibration Easy to use melts at designated temperature for easy visual inspection Superior quality free of contaminants such as sulfur, lead and halogens Traceable each marked by temperature, lot number and is NIST traceable Complain meets AWS D1.1, ASME Code Sec. I, III and VIII, ANSI/ASME Code B31.1 and B31.3