Robustly constructed for the precise application and measurement of torque values. Easy to read SI and imperial two-tone dual scale with clearly visible main and slave pointers. Double ended spindle ratchet mechanism on all models allowing torque to be measured in both clockwise and anti-clockwise directions except model 2000 N.M which has a non-ratcheting spindle. All models are accurate to ±4% of reading and have overload protection. Each tool is supplied with a traceable calibration certificate. The preferred and certified ranges of these tools is in accordance with the requirements of ISO 6789: 1992 and BS 6703. Models 400 N.M, 800 N.M and 2000 N.M have an audio visual signal that shows when the required torque is reached.