Dynamometers for laboratories, for measuring in situ and for educational purposes are available on the web. Dynamometers are accurate to ±0.3% of the load and have a range of 20% of the surface weight and provide measurements in grams (g) and Newton (N). The dynamometers with a surface weight of 5 to 1000gr have a clamp as a load support, and those of 2.5 to 50kg have a hook and most devices up to 100 t, a carabineer.