Gram-Force [gf]
The gram-force (gf) is a unit of force based on the force exerted by one gram of mass under standard gravity.
1 gf=1 g×9.80665 m/s2=9.80665×10−3 N=0.00980665 N
Example: The force due to a 500 g mass is 500 gf, which is approximately 4.9 newtons.