The following units are in the Units package.

An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI- indicate that the unit takes only positive and negative SI prefixes, respectively.  Refer to a unit in the Units package by indexing the name or symbol with the context, for example, brewster[standard]; or, if the context is indicated as the default, by using only the unit name or symbol, for example, brewster.

The units are defined as follows.

A brewster has the dimension length time squared per mass. It is defined as a square micrometer per newton.

A talbot has the dimension luminous flux time. It is defined as a lumen second.  It is also known as a lumberg.

A strontium unit has the dimension inverse time mass. It is defined as  becquerels per kilogram.