1" DR. Heavy Duty Adjustable Torque Wrench (Newton Meter & English) Dual Scale - English & Newton Meter ( N·m, ft·lb ) Design for easy torque adjustment Quality accords to DIN ISO 6789:2017 & ASME B107.300-2010 Tolerance of torque ±3%(CW) CW/CCW Direction Calibration must be done regularly to ensure accuracy. Suggested calibration period is at least every 12 months or 5000 times of usage