The gravitational metric system (original French term ) is a non-standard system of units, which does not comply with the International System of Units (SI). It is built on the three base quantities length, time and force with base units metre, second and kilopond respectively. Internationally used abbreviations of the system are MKpS, MKfS or MKS (from French or ). However, the abbreviation MKS is also used for the MKS system of units, which, like the SI, uses mass in kilogram as a base unit. Disadvantages Nowadays, the mass as a property of an object and its weight, which depends on the gravity of the earth at its position are strictly distinguished. However historically, the kilopond was also called kilogram, and only later the kilogram-mass (today's kilogram) was separated from the kilogram-force (today's kilopond). A kilopond originally referred to the weight of a mass of one kilogram. Since the gravitational acceleration on the surface of the earth can differ, one gets different values for the unit kilopond and its derived units at different locations. To avoid this, the kilopond was first defined at sea level and a latitude of 45 degrees, since 1902 via the standard gravity of . Further disadvantages are inconsistencies in the definition of derived units such as horsepower (1 PS = 75 kp⋅m/s) and the missing link to electric, magnetic or thermodynamic units. In Germany, the kilopond lost its legal status as a unit of force on 1 January 1978, when for legal purposes the SI unit system was adopted. A kilopond can be converted to the SI unit newton by multiplication with the standard acceleration gn: 1 kp = gn ⋅ 1 kg = = Units Force In English contexts the unit of force is usually formed by simply appending the suffix "force" to the name of the unit of mass, thus gram-force (gf) or kilogram-force (kgf), which follows the tradition of pound-force (lbf). In other, international, contexts the special name pond (p) or kilopond (kp) respectively is more frequent. 1 p = 1 gf = 1 g ⋅ gn = 9.80665 g⋅m/s2 = 980.665 g⋅cm/s2 = 980.665 dyn 1 kp = 1 kgf = 1 kg ⋅ gn = 9.80665 kg⋅m/s2 = 980665 g⋅cm/s2 Mass The hyl, metric slug (mug), or TME (), is the mass that accelerates at 1 m/s2 under a force of 1 kgf. The unit, long obsolete, has also been