Because the jaw is designed for HVAC/R, its clamping ability lets you measure temperatures of pipes that are fixed * at any angle, to walls or other surfaces The sensor reaches correct temperature within a minute * ATC2 jaw range: 3/8-Inch to 2 1/4-Inch pipe diameter (outside diameter) * Accuracy: +/- 4-Degree F (2-Degree C) ; ±1-Degree F (05-Degree C) after field calibration, 32 to 176-Degree F (0 to 80-Degree C) * Temperature range: -50 to 180-Degree F (-46 to 82-Degree C)