The GD-400 is a Large Force Gauge ergonomically designed and have become the industry standard for measuring force. Measurement is extremely simple, just place point of gauge arm perpendicular to the force to be measured. Reading can be taken in both directions - clockwise and counter-clockwise. This dynamometer gauge/tension gauge offers extreme precision and durability. The measuring springs are made of hard tempered annealed beryllium copper. It is equipped with maximum reading pointer. This gauge has a rounded tip and the dial diameter is 2-1/2-inch.