Force meter
A force meter is an instrument to measure the magnitude of a force. This is often just a spring contained within a cylinder that has a scale to mark the extension of the spring produced by the force. In the International System of Units, the unit of force is the newton (symbol N). A force meter that measures force in newtons may be referred to as a newtonmeter.
Kilogram-force
Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI.