| style="text-align:center;"| Wb | magnetic flux | style="text-align:center;"| kg⋅m2⋅s−2⋅A−1 | style="text-align:center;"| V⋅s |- ! scope="row" | tesla | style="text-align:center;"| T | magnetic flux density | style="text-align:center;"| kg⋅s−2⋅A−1 | style="text-align:center;"| Wb/m2 |- ! scope="row" | henry | style="text-align:center;"| H | inductance | style="text-align:center;"| kg⋅m2⋅s−2⋅A−2 | style="text-align:center;"| Wb/A |- ! scope="row" | degree Celsius | style="text-align:center;"| °C | temperature relative to 273.15 K | style="text-align:center;"| K | |- ! scope="row" | lumen | style="text-align:center;"| lm | luminous flux | style="text-align:center;"| cd⋅sr | style="text-align:center;"| cd⋅sr |- ! scope="row" | lux | style="text-align:center;"| lx | illuminance | style="text-align:center;"| cd⋅sr⋅m−2 | style="text-align:center;"| lm/m2 |- ! scope="row" | becquerel | style="text-align:center;"| Bq | activity referred to a radionuclide (decays per unit time) | style="text-align:center;"| s−1 | |- ! scope="row" | gray | style="text-align:center;"| Gy | absorbed dose (of ionising radiation) | style="text-align:center;"| m2⋅s−2 | style="text-align:center;"| J/kg |- ! scope="row" | sievert | style="text-align:center;"| Sv | equivalent dose (of ionising radiation) | style="text-align:center;"| m2⋅s−2 | style="text-align:center;"| J/kg |- ! scope="row" | katal | style="text-align:center;"| kat | catalytic activity | style="text-align:center;"| mol⋅s−1 | |- | colspan="5" |Notes|} Dimensionless units The unit of a dimensionless quantity is one (symbol 1), but it is rarely shown. The radian and steradian are also dimensionless quantities, but use the symbols rad and sr respectively. Prefixes Prefixes are added to unit names to produce multiples and submultiples of the original unit. All of these are integer powers of ten, and above a hundred or below a hundredth all are integer powers of a thousand. For example, kilo- denotes a multiple of a thousand and milli- denotes a multiple of a thousandth, so there are one thousand millimetres to the metre and one thousand metres to the kilometre. The prefixes are never combined, so for example a millionth of a metre is a micrometre, not a millimillimetre. Multiples of the kilogram are named as if the gram were the base unit, so a millionth of a kilogram is a milligram, not a microkilogram. When prefixes are used to form multiples and submultiples of SI base and derived units, the resulting units are no longer coherent. The BIPM specifies 24 prefixes for the International System of Units (SI): Non-SI units accepted for use with SI Many non-SI units continue to be used in the scientific, technical, and commercial literature. Some units are deeply embedded in history and culture, and their use has not been entirely